BOGOTA, Feb. 25 (CGTN) -- The United States targeted Venezuela's government with new sanctions on Monday and called on allies to freeze the assets of its state-owned oil company PDVSA after deadly violence blocked humanitarian aid from reaching the country over the weekend.

As Colombia's foreign minister warned about "credible threats to the life" of Venezuela's opposition leader Juan Guaido, the Trump administration also took its pressure campaign to the United Nations Security Council, asking it to discuss the situation in Venezuela, diplomats said.

The U.S. Treasury Department's sanctions were imposed on four Venezuelan state governors allied with the government of President Nicolas Maduro, blocking any assets they control in the United States.

The new sanctions were announced in Bogota as U.S. Vice President Mike Pence and Guaido met with members of the Lima Group, a bloc of nations from Argentina to Canada dedicated to peaceful resolution of the political and economic crisis in Venezuela.

Pence said the United States would stand by Guaido until freedom was restored. 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 against the OPEC member.

"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."

While the day presented a united regional front against Maduro, who is widely accused of coming to power through fraudulent elections, there was no clear sign that the latest measures would succeed in pushing him toward the exit.

On a day that began with Guaido urging "all options" to be considered to remove Maduro, the threat of military intervention seemed if anything weaker after the meeting.

In a joint statement at the close of the meeting, the Lima Group said Maduro was a threat to peace and security in the region and called for his immediate exit, a democratic transition and free elections.

The statement added that the group "reiterates the conviction that the transition to democracy must be conducted by the Venezuelans themselves peacefully and within the framework of the Constitution and international law."