Deadly clashes break out in Venezuela's border towns as opposition tries to bring in aid
Troops fire tear gas at crowds trying to break through government blockades
At least one aid truck goes up in flames on the Colombia-Venezuela border
Self-declared interim President Juan Guaidó urges the military to allow aid in
President Nicolás Maduro warns this would open the way for US military intervention
Several members of Venezuela's security forces have defected
Image source, AFP/Getty ImagesMeanwhile, supporters of Nicolás Maduro held a rally in Venezuela's capital of Caracas.
Image source, AFP/Getty ImagesDemonstrators carried posters that read "Yankee go home!", accusing the US of intervening in Venezuela's affairs.
Diario La Opinión, a newspaper in Cúcuta on the Colombian side of border, has tweeted this video of protests continuing at the Simón Bolívar bridge.
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Speaking to reporters earlier in the Colombian border city of Cúcuta, Juan Guaidó called for the Venezuelan military to abandon their support for President Maduro.
He said: "I've made a clear call to the armed forces.
"Welcome to the right side of history. Welcome to those soldiers that today have moved to the right side of the constitution. Welcome.
"There is a clear sign today that the amnesty and guarantees are there for all those soldiers who are willing to take in and help the Venezuelan people and, above all, to respect our constitution."
Another member of Venezuela's special police force has defected, reports say.
Live footage showed the officer crossed into Colombia via the Simón Bolívar bridge - to loud cheers from crowds.
Image source, Getty ImagesGrowing discontent in Venezuela, fuelled by hyperinflation, power cuts and food and medicine shortages, has led to a deep political crisis.
Here's our explainer of the fast changing situation in nine charts.
Image source, ReutersA convoy of trucks with humanitarian aid will be unloaded at the Simón Bolívar bridge on Colombia's side and the aid will be then transported by a human chain across the border, Colombia officials are as quoted as saying by Reuters.
Latest pictures from the area showed Venezuelan opposition politicians and their supporters on the bridge, urging Venezuelan troops to let the aid through.
Image source, ReutersDemonstrators earlier set a bus alight as security forces took their positions in Ureña, Venezuela.
Image source, ReutersVenezuelan troops fired tear gas at protesters and those seeking to receive the humanitarian aid in the city, witnesses said.
Image source, ReutersVenezuela crisis: The moment troops crash through border
People disperse as two Venezuelan armoured vehicles drive from the Venezuelan side of Simón Bolívar bridge towards Colombia.
Image source, AFPAccording to Colombian authorities, a number of Venezuelan national guard troops deserted after crossing two border bridges that have been closed on the orders of Mr Maduro's government.
Venezuelan soldiers were reportedly detained by Colombian police after crossing the border to Cucuta.
Image source, AFPFollowing Mr Guaidó's tweet suggesting that the first humanitarian aid truck has crossed into Venezuela from Brazil, reports are emerging that a convoy of trucks has left from several warehouses in Colombia for the border, and should be arriving shortly.
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Paraguayan President Abdo Benítez has posted footage showing Juan Guaidó on a truck with humanitarian aid.
Mr Guaidó earlier said (see our 15:50 entry) that the aid was on its way to Venezuela in a peaceful manner.
The self-declared president was speaking at the Colombia-Venezuela border.
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Juan Guaidó says the "first shipment of humanitarian aid" has now crossed into Venezuela from Brazil.
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An earlier tweet by BBC producer Haley Thomas, external, at the Colombian border, suggests that trucks carrying humanitarian aid are due to arrive shortly at the Simón Bolívar bridge in Cúcuta.
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Mr Guaidó also says the humanitarian aid is on its way to Venezuela in a peaceful manner, adding that it will "save lives".
Image source, ReutersJuan Guaidó arrives in Cucuta, Colombia
Self-declared interim President Juan Guaidó has just spoken on the Colombia-Venezuela border.
"Welcome to the right side," he told defected Venezuelan soldiers.
He said any soldiers who joined the opposition would receive “amnesty and guarantees” from his interim government.
Venezuelan President Nicolás Maduro says people are "mobilised" in the capital Caracas and across the country.
"Let us all go to the streets to defend our independence," he urges the nation.
Mr Maduro adds that "there will be no war" in Venezuela and that peace will "triumph".
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Venezuela crisis: Is Maduro or Guaidó in charge?
As a political crisis in Venezuela escalates, many people ask who is really in charge in the country?
Here's our explainer with the BBC's Paul Adams.
Guillermo Olmo, BBC Mundo, Ureña, Venezuela
Image source, AFP/Getty ImagesIt's been a difficult day here on the Venezuelan side.
We found locals getting angry because they found the border was closed - these people normally make a living across the border. Then it turned ugly in Ureña.
We witnessed protesters lunging to break one of the barriers, but the national guard started firing tear gas and pellets.
People were shouting at the national guard asking them why, in their words, they were serving a dictator and not serving their own people.
We had to run away to avoid being hurt but there is still a lot of tension in the air, with a heavy military presence everywhere.
Image source, ReutersAs demonstrators take to the streets in the Venezuelan city of Ureña near the Colombian border, images reveal the severity of the clashes with security forces.
In a series of photos, one protester can be seen running into a strip of barbed wire as debris burns in the road, causing him to fall to the floor.
Image source, Reuters
Image source, ReutersDemonstrators were also seen throwing rocks at the security forces.
Image source, ReutersCrowds also gathered at the Simon Bolivar bridge on the border with Cucuta.
Image source, EPAIn the city of Ureña, where the Tienditas bridge connects Venezuela to the Colombian city of Cúcuta, there have been fierce clashes between civilians and Venezuelan security forces.
A reporter with the UK's Telegraph newspaper, Harriet Alexander, external, has travelled to the area and is tweeting as events unfold.
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With news that several Venezuelan soldiers have now left their posts at the Colombian border, the BBC's Orla Guerin , externalhas tweeted an image from the scene of civilians urging troops to allow aid deliveries through.
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