Venezuelan authorities have blockaded a second bridge to Colombia amid fresh skirmishes between protesters and security forces loyal to the embattled leader Nicolás Maduro.

The move came as opposition leader Juan Guaidó travelled to Brazil to shore up international pressure on Maduro following an inconclusive meeting of regional leaders in Colombia earlier this week.

Early on Wednesday, two shipping containers were positioned across the Simón Bolívar bridge, a major pedestrian crossing between the two countries, following days of sporadic violence.

The bridge was the focus of a failed weekend attempt to bring US food aid into the country as part of Guaidó’s campaign campaign to force Maduro from power.

Dozens were injured on Saturday as anti-government protesters clashed with Venezuela’s national guard and pro-Maduro gangs at the bridge and another crossing near near the Colombian city of Cúcuta. In circumstances that remain unclear, at least two trucks carrying the aid caught fire during the violence.

Footage broadcast on Colombian television on Wednesday showed a burned-out truck bed in front of the shipping containers, which had been positioned overnight across the Simón Bolívar bridge.

Last month, Venezuelan authorities barricaded the nearby Tienditas bridge with two containers and an oil truck. That bridge was finished in 2016 but never inaugurated.

The Colombian border has been closed to most vehicles since 2015 following a string of disputes between the two countries, and on Saturday Maduro closed all Venezuela’s borders.

Colombia closed four crossings from its side on Saturday evening, reopening them on Monday afternoon.

Saturday’s aid effort was intended to weaken Maduro by triggering a flood of military defections. That did not happen, but Colombian migration authorities reported that around 250 military officials have crossed the border, joining a steady stream of Venezuelan refugees leaving the country via unpoliced routes.

After Saturday’s violence, Guaidó – who has been recognized as Venezuela’s rightful president by the US and 50 other countries – travelled to Bogotá and met with the US vice-president, Mike Pence, and Latin American leaders.

Guaidó, who was officially barred from travel, was set to arrive in Brazil late on Wednesday for a meeting with the far-right leader Jair Bolsonaro, an outspoken opponent of Maduro.

Maduro’s vice-president, Delcy Rodríguez, will travel to Moscow for talks with the Russian foreign minister, Sergei Lavrov, on Friday. Russia has been among Maduro’s staunchest allies during the crisis.

Meanwhile, unrest continued near Venezuela’s eastern border with Brazil after violence that left at least three people dead and dozens injured over the weekend.

On Tuesday morning, soldiers took control of an airport in the town of Santa Elena de Uairén, which was the focus of clashes between Venezuelan soldiers and indigenous protesters.

Witnesses say they were attempting to travel to Maurak, where members of the Pemon indigenous community had captured 30 soldiers on Saturday.