At least two people have been killed and 300 injured as Venezuelan security forces fired tear gas on protesters trying to deliver humanitarian aid from neighbouring countries.

The day of violence saw police and activists square off on two bridges connecting Venezuela with Colombia.

Juan Guaidó, the man the US recognises as Venezuela's interim president, made repeated calls for the military to join him in the fight against Nicolas Maduro's "dictatorship".

An estimated 60 soldiers heeded his call, although most were lower in rank and did not seem to dent the higher command's continued loyalty to Mr Maduro's socialist government.

Almost 200 tonnes of aid in a convoy of trucks has been waiting to cross several border bridges - including food and medicine - and the tear gas was fired as protesters tried to stop the aid from being destroyed.

Mr Guaidó said he will meet with the Lima Group of Nations - 14 countries seeking an end to the crisis in Venezuela - in Bogota on Monday with US Vice President Mike Pence.

Demonstrators throw stones in clashes with the security forces at the Francisco de Paula Santander international bridge Bridge linking Cucuta, Colombia, and Urena, Venezuela, during an attempt to cross humanitarian aid over the border into Venezuela | Image: Elyxandro Cegarra/Zuma Press/PA Images

The interim president is hoping diplomacy could lead to a breakthrough in the crisis and apply further pressure on Mr Maduro.

Mr Guaidó made an impassioned plea to troops, as he stood alongside a warehouse where 600 tonnes of supplies have been stockpiled.

He said: "How many of you national guardsmen have a sick mother? How many have kids in school without food?

"You don't owe any obedience to a sadist... who celebrates the denial of humanitarian aid the country needs."

One man, who was left with a bloody wound after being struck on the forehead with a tear gas canister during Saturday's unrest, said: "They burned the aid and fired on their own people. That's the definition of dictatorship."

Protesters formed a human chain to pass back as much salvaged aid as they could as smoke billowed from barricades built to stop the supplies getting in. Other demonstrators threw rocks at heavily armed police.

Venezuelan officials have closed the border with Colombia, Brazil and the island of Curacao and have been cracking down on those trying to keep them open.

Mr Maduro said he had cut all diplomatic relations with Colombia's "fascist government" and was expelling its diplomats in response to its support for Mr Guaidó.

An injured demonstrator being treated at the international bridge by Colombian police | Image: Rafael Hernandez/DPA/PA Images

Speaking to supporters in Caracas, the Venezuelan capital, the embattled president said: "Patience is exhausted, I can't bare it anymore, we can't keep putting up with Colombian territory being used for attacks against Venezuela."

Opponents claim Mr Maduro presided over a fraudulent election and has let the economy go to ruins with rampant inflation and people struggling to get food and medicine.

Most of the aid at the Colombia border has been provided by the US, which has recognised Mr Guaidó as the interim president despite Mr Maduro refusing to stand down.

Venezuelan authorities regard the plan to bring in aid as a veiled US-backed invasion.

Mr Guaidó, the head of Venezuela's National Assembly, declared himself interim president under the constitution on January 23rd.

He has been backed by dozens of countries, including Ireland.

On Friday, he attended a concert staged by British entrepreneur Richard Branson, in Cucuta, on the Colombian side of the border, opposite Urena.

Mr Guaidó met Colombian president Ivan Duque at the Live Aid-style event, despite Mr Maduro forbidding him from leaving the country.