Updated

The Latest on Venezuela's political crisis (all times local):

1:35 p.m.

Renewed clashes have broken out between protesters and Venezuelan national guardsmen at the border with Brazil.

Dozens of Venezuelans who had come to the Brazilian border city of Pacaraima began throwing rocks across the closed border at Venezuelan troops, who responded with tear gas and buckshot.

Globo television broadcast images of a Brazilian soldier advancing to the border line on Sunday to appeal for calm on the part of the Venezuelan soldiers and to urge protesters and journalists to move back.

Local officials say dozens of people were injured in more violent clashes on Saturday as Venezuelan forces blocked aid shipments from crossing the border.

Brazilian Navy Col. George Feres Kanaan is coordinating humanitarian logistics in Roraima state, and he says two Venezuelan National Guard sergeants sought refuge in Brazil on Saturday, abandoning President Nicolas Maduro's forces.

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11 a.m.

Officials in the Brazilian border state of Roraima say they've treated 22 Venezuelans who suffered bullet or buckshot wounds during a confrontation over aid shipments.

A spokesman for Gov. Antonio Denarium says 18 of those required surgery. And he says dozens of other Venezuelans are being treated for other injuries suffered in Saturday's clashes at the border city of Santa Elena.

The spokesman says the influx has overwhelmed the health system in the state capital of Boa Vista and officials plan to declare a state of emergency for the public health sector on Monday. That would give officials the ability to more quickly buy medicine and to contract rooms at private hospitals.

Venezuelan President Nicolas Maduro is blocking aid shipments organized by the opposition that are meant to undermine his rule.

The border was closed for a third straight day on Sunday.

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10 a.m.

Venezuelan migrants are helping clean debris from a bridge where troops loyal to President Nicolas Maduro earlier fired tear gas on activists trying to deliver humanitarian aid in violent clashes that left two people dead and some 300 injured.

Colombian President Ivan Duque has reinforced security around two international bridges near the city of Cucuta and ordered them closed for 48 hours to allow for the clean-up effort.

Duque says that acts of "barbarism" committed by Maduro's troops in blocking the delivery of humanitarian aid require a forceful international response — something that could come as early as Monday, when U.S. Vice President Mike Pence travels to the Colombian capital for an emergency summit on Venezuela with foreign ministers from more than a dozen mostly conservative Latin American and Caribbean states.