Image source, EPA/TONY VRAILAS/MARINETRAFFIC.COM

How did disaster strike Beirut? Well, the huge blast that devastated parts of the city has been blamed on the detonation of 2,750 tonnes of ammonium nitrate stored at the port.

People have expressed anger and disbelief that such a large quantity of potentially explosive material was kept inside a warehouse without any safety measures for more than six years, so close to the centre of the city.

The government has not named the source of the ammonium nitrate, but the same amount of the chemical arrived in Beirut in November 2013 on a Moldovan-flagged cargo ship, the MV Rhosus.

Read more here about how the cargo is thought to have arrived in Lebanon.

The President of the European Council, Charles Michel, has said he will travel to Beirut on Saturday “to convey Europe’s solidarity with the people in Lebanon”.

He said he would meet President Michel Aoun, Prime Minister Hassan Diab, and the Speaker of Parliament, Nabih Berri.

On Thursday, French President Emmanuel Macron called for "profound change" from Lebanon's leadership following the deadly port blast.

During his visit to Beirut, Mr Macron also called for an international investigation.

At least 149 people are now known to have died in the Beirut explosion that also left thousands injured.

The port area that took the brunt of Wednesday's blast has been completely devastated. BBC Arabic's Candice Hatem filmed these exclusive images.

Imogen Foulkes
BBC News, Geneva

Image source, Reuters

UN aid agencies are now warning of a humanitarian crisis in Lebanon, with food supplies likely to be interrupted and prices likely to rise because of the damage to the port.

A spokeswoman for the World Food Programme (WFP) in Geneva said Lebanon imported 85% of its food.

The WFP is sending 5,000 food parcels to Lebanon, each designed to support a family of five for one month.

The World Health Organization said that Lebanon’s already fragile health system had been seriously damaged, with three hospitals virtually destroyed by the blast.

The WHO is now sending 1,000 trauma kits to support treatment of the most serious injuries and burns.

However, 17 containers of personal protective equipment, stored in a WHO warehouse in Beirut and intended to support Lebanon’s fight against Covid-19, were destroyed in the explosion.

Meanwhile, the UN refugee agency, UNHCR, is releasing its supplies of tarpaulins and other temporary shelter materials to all who are in need.

An agency spokesman warned that Syrian refugees, among the poorest in Lebanon, were especially vulnerable, saying that "the massive explosion adds to the already severe economic crisis that had pushed many Lebanese and refugees there deeper into poverty".

Rescue workers in Lebanon have been digging through the rubble looking for survivors of Tuesday's devastating explosion.

Here is what we know so far.

The disaster was preceded by a large fire at the Port of Beirut, on the city's northern Mediterranean coast. In videos posted on social media white smoke could be seen billowing from Warehouse 12, external, next to the port's huge grain silos.

Shortly after 18:00 (15:00 GMT), the roof of the warehouse caught alight and there was a large initial explosion, followed by a series of smaller blasts that some witnesses said sounded like fireworks going off.

About 30 seconds later, there was a colossal explosion that sent a mushroom cloud into the air and a supersonic blastwave radiating through the city.

That blastwave levelled buildings near the port and caused extensive damage over much of the rest of the capital, which is home to two million people. Hospitals were quickly overwhelmed.

Read more details about the blast here.

Quentin Somerville
Middle East Correspondent

Beirut is a place I feel nostalgic about even when I'm in it.

It's fixed in our collective memories as a place of glamour and danger. I've lived here five years, and sometimes it's hard to separate these visions of past and present.

One image, fixed in my head from childhood, is from the civil war. It shows a bride, Areej Estephan and her groom, crossing the green line, the no-man's land separating the factions in the war which ran from 1975 to 1990.

In the photograph by Georges Semerjian, Areej is wearing a white rented wedding dress, her husband Abed Joumaa, a white tux. All around them is destruction. It's a snap of the surreal; beauty and dysfunction, captured in a single frame.

Thirty-seven years later another bride, Dr Israa Seblani stood not far from where Areej once posed, in her own wedding dress. She is filmed with a dazzling smile and brilliant hijab and long white train.

As the cameraman Mahmoud Nakid pans down, a few kilometres away a massive detonation takes place, the deadly explosion from Beirut's port, Dr Seblani's dress ripples with the shock wave as the dust and debris falls and she runs for cover.

Read Quentin's piece in full here.

Welcome to our live coverage of the situation in Beirut in response to the massive explosions which destroyed large parts of the city earlier this week.

You join us amid continuing anger after security forces deployed tear gas on Thursday evening on demonstrators near Lebanon’s parliament.

Many in Lebanon say government negligence led to the explosion, which killed at least 149 people and injured about 5,000 others.

Dozens of people are still unaccounted for after Tuesday’s blasts, which destroyed entire districts in the capital, and reduced homes and businesses to rubble.