The United States has targeted Venezuela's government with new sanctions and called on allies to freeze the assets of its state-owned oil company PDVSA.
It follows deadly violence that blocked aid from reaching the crisis-hit country during the weekend.
The US also took its pressure campaign to the United Nations Security Council, asking that body to discuss the situation in Venezuela, diplomats said.
The US Treasury Department's sanctions were imposed on Monday on four Venezuelan state governors allied with the government of embattled President Nicolas Maduro, blocking any assets they control in the United States.
The new sanctions were announced in Bogota as US Vice President Mike Pence and opposition leader Juan Guaido met with members of the Lima Group, a bloc of nations from Argentina to Canada dedicated to peaceful resolution of the Venezuelan crisis.
Pence said the United States would stand by Guaido until freedom was restored to the OPEC member. He called for all Lima Group nations to immediately freeze PDVSA's assets and to transfer ownership of Venezuelan assets in their countries from Maduro's "henchmen" to Guaido's government-in-waiting.
He also said tougher measures were coming.
"In the days ahead ... the United States will announce even stronger sanctions on the regime's corrupt financial networks," Pence said. "We will work with all of you to find every last dollar that they stole and work to return it to Venezuela."
Washington wants the 15-member UN Security Council to formally call for free, fair and credible presidential elections with international observers. Russia, which along with China has major investments in Venezuela's energy sector and back Maduro, proposed a rival draft resolution.
Violence escalated during the weekend when the convoy of trucks with food and medicines was blocked by soldiers and armed groups loyal to Maduro. He says the aid efforts are part of a US-orchestrated coup against Venezuela.
Four people have been killed, 58 have suffered bullet wounds and at least 32 arrested in unrest since Friday, local rights group Penal Forum said in a press conference.
