Leo Kelion
Technology desk editor

The hearing has had to pause because of a technical problem with one of the feeds - presumably that of Amazon's Jeff Bezos, who hasn't spoken in a while.

So far there's been lots of accusations thrown the tech CEOs way, but little if any damage done.

A consequence, perhaps, of switching topic and leader after relatively brief sessions, helping the well-prepared business chiefs swat away the claims of wrongdoing lobbed their way.

Image source, Reuters

Republican congressman Matt Gaetz claimed that Google collaborates with Chinese universities that take "millions upon millions of dollars from the Chinese military" and noted that tech investor Peter Thiel had previously accused the company of "treason".

Sundar Pichai - chief executive of parent company Alphabet - denied that his employees were acting against American interests.

"We are not working with the Chinese military it's absolutely false," he said.

"What we do in China, compared to our peers, it's very very limited in nature.

"Our AI work in China is limited to a handful of people working on open source projects."

We are an hour and a half in to the hearing and yet to hear from Amazon's Jeff Bezos, apart from his opening remarks. Most of the questions have been for Facebook's Mark Zuckerberg and Alphabet's Sundar Pichai.

Image source, EPA

The Democrat congressman Henry Johnson raised concerns about Apple's App Store, suggesting its moderators made up rules "as they go" and then arbitrarily interpreted them.

He added that it appeared that the rules were sometimes "changed to benefit Apple at the expense of [third-party] developers" and also discriminated between different creators.

"Sir, we treat every developer the same," Mr Cook responded.

"We have open and transparent rules... we do look at every app before it goes on. But those apps, those rules apply evenly to everyone."

Mr Johnson went on to suggest there was nothing to stop Apple raising its cut of app sales from the existing level of 30% to 50%.

Mr Cook replied that he strongly disagreed with this.

"There is a competition for developers," the Apple chief said, saying software creators could switch their efforts to Android, Windows, Xbox or PlayStation.

Republican congressman Jim Sensenbrenner asked Mark Zuckerberg why a post by the US president's son, Donald Trump Jr, had been taken down because it discussed the efficacy of the drug hydroxychloroquine.

Mr Zuckerberg noted that happened on a rival social network, but answered the point.

"I think what you might be referring to happened on on Twitter, so it's hard for me to speak to that. But I can talk to our policies.

"We do prohibit content that will lead to imminent risk of harm.

"We do not want to become the arbiters of truth... [but] if someone is going to go out and say that hydroxychloroquine is proven to cure Covid, when in fact it has not been proven to cure Covid, and that statement could lead people to to take a drug that that in some cases, some of the data suggests that it might be harmful to people - we think that we should take that down."

Image source, Getty Images

Rory Cellan-Jones
Technology correspondent

During the hour's delay before the hearing got underway, Amazon's share price rose by about 0.5%.

I'm not sure how much richer that makes Jeff Bezos, but it is probably more than $500m.

Committee chair David Cicilline began the cross-examination of Google's Sundar Pichai by accusing the company of having a "conflict of interest" between serving the public information and its own business model, which sells ads and seeks to keep users on its own sites.

Mr Pichai responded that Google needed its users to trust it to keep them coming back, and added that for the vast majority of search queries it didn't show any ads at all.

In his opening remarks, Facebook CEO Mark Zuckerberg, included an apparent warning that if the US tech model doesn't win out, another will.

"Facebook stands for a set of basic principles, giving people voice and economic opportunity, keeping people safe upholding democratic traditions like freedom of expression and voting and enabling an open and competitive marketplace.

"These are fundamental values for most of us, but not for everyone in the world, not for every company we compete with or the countries they represent.

"And as global competition increases. There is no guarantee that our values will win out."

Apple's chief executive Tim Cook has given his prepared statement to the Judiciary Committee.

The company is expecting to face criticism of the 30% cut it takes from software sold via its App Store, particularly since it won't let commercial apps be installed natively by other means on iPhones and iPads.

"For the vast majority of apps on the App Store, developers keep 100% of the money they make," Mr Cook said.

"The only apps that are subject to a commission are those where the developer acquires a customer on an Apple device and where the features or services would be experienced and consumed on an Apple device.

"In the App Store's more than 10 year history, we have never raised the commission or added a single fee. In fact, we've reduced it for subscriptions and exempted additional categories of apps."

In his opening remarks Alphabet CEO Sundar Pichair argued the company's innovation brought widespread benefits.

"Using Android thousands of mobile operators build and sell their own devices without paying any licensing fees to us," he said.

"This has enabled billions of consumers to afford cutting-edge smartphones, some for less than $50."

Amazon CEO Jeff Bezos has given his prepared opening remarks. He discussed the company's founding and says that the US business climate made his success possible.

"The trust customers put in us every day has allowed Amazon to create more jobs in the United States over the past decade, than any other company," he said.

"Hundreds of thousands of jobs.

"Amazon employees make a minimum of $15 an hour, more than double the federal minimum wage. And we offer the best benefits.

"Here in the US, we nurture entrepreneurs and start-ups, with stable rule of law, the finest university system in the world, the freedom of democracy and a deeply accepted culture of risk taking."

The four tech chief executives are all giving testimony by remote video links.

They all swore in over the feeds ahead of Amazon's Jeff Bezos giving the first opening statement.

Republican Jim Jordan makes his feelings very clear in his opening statement.

"Big tech is out to get conservatives," he said.

"That's a fact."

He then gave a long list of what he said were examples of tech firms targeting conservative platforms and voices.

"We all think the free market's great. We think competition's great. We love the fact these are American companies. But what's not great is censoring people."

Jim Sensenbrenner, the most senior Republican member of the committee has said he is concerned that the tech companies are politically biased.

"Companies like Facebook, Google's YouTube and Twitter have become the public square of today, where political debate unfolds," he said.

"But reports that dissenting views - often conservative views - are targeted or censored is seriously troubling.

"Conservatives are consumers too, and they need the protection of the antitrust laws.

"The power to influence debate carries with it remarkable responsibilities...

"Your companies are large, that's not a problem. Your companies are successful. That's not a problem either.

"But I want to leave here today with a more complete picture of how your individual companies use your size success and power, and what it means to the American consumer."

Other Republican members of the committee have made similar claims of bias.

Committee chair David Cicilline used his opening address to attack the power of big tech.

"When the American people confronted monopolist in the past, via the railroads or the oil tycoons, or AT&T and Microsoft, we took action to ensure no private corporation controls our economy, or our democracy," he said.

"We face similar challenges today.

"As gatekeepers of the digital economy these platforms enjoy the power to pick winners and losers to shake down small businesses and enrich themselves while choking off competitors.

"Their ability to dictate terms, call the shots, up-end entire sectors and inspire fear represent the powers of a private government.

"Our founders would not bow before a king, nor should we bow before the emperors of the online economy."

The much-anticipated hearing has begun, an hour later than scheduled. The chairman - Democratic congressman David Cicilline - is giving his opening remarks. He says "dominance" of Amazon, Apple, Google and Facebook will be addressed. We expect to hear from their bosses soon after.

While we wait for the delayed hearing to get underway, BBC tech reporter Cody Godwin has an idea about how to fill the time:

US President Donald Trump has weighed in ahead of the hearing - he said he would use executive orders against the tech firms if Congress doesn't act.

President Trump has used executive orders to target tech firms before.

Earlier this year he signed an order aimed at removing some of the legal protections given to social media platforms soon after Twitter applied "fact-checking" labels to some of his posts.

Twitter said the order threatened free speech, and legal experts have cast doubt over whether it would work.

The hearing is now due to begin at 1800 BST (1300 EST). The reasons for the delay are unclear.

Image source, Getty Images

One tech chief who hasn't been invited to today's party is Kevin Mayer, who recently quit Disney to become TikTok's chief executive. But ahead of the hearing he published blog in which he takes a dig at Facebook, external.

Facebook's CEO has previously accused TikTok of censoring protesters, asking: "Is that the internet that we want?" And Mark Zuckerberg is expected to suggest today that Facebook should not be over-regulated to prevent its apps losing out to TikTok and other Chinese rivals.

But Mr Mayer has got his defence in first.

"To those who wish to launch competitive products, we say bring it on," he wrote.

"Facebook is even launching another copycat product, Reels (tied to Instagram), after their other copycat Lasso failed quickly. But let's focus our energies on fair and open competition in service of our consumers, rather than maligning attacks by our competitor – namely Facebook – disguised as patriotism and designed to put an end to our very presence in the US."Read more about this development