WASHINGTON, Feb. 25 (Xinhua) -- As the U.S.-Venezuela confrontation escalated over the entry of aid into the South American nation, the Trump administration on Monday enhanced its carrot-and-stick pressure campaign toward the Maduro government, slapping sanctions against four officials and announcing additional humanitarian assistance.

In a statement issued Monday, the U.S. Department of the Treasury announced that it will sanction four state governors aligned with President Nicolas Maduro "for standing in the way of severely needed humanitarian assistance."

The move, banning them from financial or commercial transactions with U.S. citizens or entities, came amid an aid standoff in which the United States and other regional countries, in coordination with the Venezuelan opposition, declared a plan to deliver humanitarian aid to Venezuela.

Denying the existence of a humanitarian crisis, the Venezuelan government has refused to let the aid cross the border and called the aid operation a U.S.-orchestrated show designed to lead to an eventual invasion.

In a separate statement issued Monday regarding the sanction, the State Department noted that "we reaffirm our call on Venezuelan officials and security forces to allow urgently needed food and medicine to enter and be distributed throughout the country."

"U.S. sanctions need not be permanent," it said. "The United States will continue to take appropriate action to respond to the situation in Venezuela as it develops."

The U.S. action coincided with the trip of U.S. Vice President Mike Pence, who attended a meeting of the Lima Group in Bogota, Colombia on Monday to discuss the situation in Venezuela with regional nations.

During the meeting, Pence lashed out at the Maduro government for its refusal to let the U.S. aid cross its border, and reiterated the U.S. support for the Venezuelan opposition leader Juan Guaido.

Saying that the Trump administration is "identifying new areas along the border where we can pre-position additional aid for the struggling people of Venezuela," Pence said that "the United States will provide an additional 56 million U.S. dollars to support our partners in the region as you come to the aid of the Venezuelan people" who fled from their nation.

He also said that "in the days ahead as well, the United States will announce even stronger sanctions on the regime's corrupt financial networks."

As for other regional countries, Pence urged all Lima Group members to immediately freeze the assets of Venezuela's national oil company PDVSA, transfer ownership of Venezuelan assets in their countries from the Maduro government to Guaido's followers, restrict visas for Maduro's inner circle, and vote to recognize Guaido's representative at the Inter-American Development Bank.

The State Department later said in a statement that the new assistance that Pence announced "complements the aid that the United States and its partners pre-positioned near the Colombia- and Brazil-Venezuela borders over the last few weeks."

"The United States will continue to pursue all avenues to increase humanitarian assistance to Venezuelans both inside and outside Venezuela," it said.

The Trump administration recognized Guaido as the nation's "interim president" on Jan. 23, days after Maduro was inaugurated for a second term as Venezuelan president.

In response to Washington's support for Guaido, Maduro announced that he was severing "diplomatic and political" ties with the United States, ordering all the U.S. diplomatic and consular personnel to leave Venezuela in 72 hours.

On Friday, Venezuelan Vice President Delcy Rodriguez announced the closure of three bridges connecting the country with Colombia.

Maduro announced on Saturday the severance of his country's diplomatic and political relations with Colombia, following the latter's support for Venezuela's opposition and military defectors.