Venezuelan military officers blocked a bridge on the border with Colombia ahead of an anticipated humanitarian aid shipment, as Opposition leader Juan Guaidó stepped up his challenge to President Nicolás Maduro’s authority. Earlier on Tuesday, the Opposition-dominated National Assembly warned the armed forces, which make up Mr. Maduro’s power base, not to cross a “red line” by blocking aid.

Mr. Guaidó claims that up to 3,00,000 people face death if the aid is not delivered. However, Mr. Maduro said humanitarian aid would be the forerunner of a U.S.-led invasion, insisting that “no one will enter, not one invading soldier”.

Venezuelan military officers used a tanker truck and huge shipping container to block access to the Tienditas bridge, which links Cucuta, Colombia to Urena, Venezuela.