U.S. Treasury Secretary Steven Mnuchin attends a press briefing at the White House in Washington D.C. Jan. 28, 2019. The United States on Monday slapped sanctions on Venezuela's state-owned oil firm Petroleos de Venezuela, S.A., or known as PDVSA. (Xinhua/Ting Shen)

WASHINGTON, Jan. 28 (Xinhua) -- The United States on Monday imposed sanctions on a state-owned oil firm in Venezuela, the latest move of the Trump administration to mount pressure on President Nicolas Maduro to cede power to the opposition.

The sanctions on Petroleos de Venezuela, S.A., or PDVSA, will block 7 billion U.S. dollars in assets and could result in a loss of 11 billion dollars in sales next year, U.S. National Security Adviser John Bolton told a White House briefing.

Washington's tough sanctions against Venezuela came days after it recognized the opposition leader Juan Guaido as interim president of the Latin American country, denouncing incumbent President Nicolas Maduro who won the elections last year with over two thirds of the votes.

The U.S. Treasury described PDVSA as "a primary source of Venezuela's income and foreign currency" in a statement released later in the day, saying that the blacklist could help "prevent further diverting of Venezuela's assets by Maduro."

As a result of Treasury's action, all property and interests in property of PDVSA subject to U.S. jurisdiction are blocked, and U.S. citizens are generally prohibited from engaging in transactions with them.

In an effort to mitigate impact of the designation, U.S. Treasury Secretary Steven Mnuchin, who also attended the White House briefing, told reporters that oil supplies were sufficient to guarantee only "very modest" effect on U.S. gas prices in the short term.

In Monday's statement, the Treasury also declared that the path to sanctions relief is "through the expeditious transfer of control to the Interim President or a subsequent, democratically elected government."

Meanwhile, the Treasury has been issuing general licenses that authorize certain transactions and activities related to PDVSA and its subsidiaries within specified timeframes.

The United States, Brazil and some other countries have recognized Guaido's presidency, with U.S. President Donald Trump warning that "all options are on the table."

Maduro, in response, announced the severing of "diplomatic and political" ties with the United States. Washington later said that it would conduct diplomatic relations through the government of "interim president."

Mnuchin also said in the Treasury's statement that the United States will "continue to use the full suite of its diplomatic and economic tools to support" Guaido, head of the National Assembly, who declared himself interim president during an anti-government rally.

Maduro on Sunday visited a military base in the northern state of Carabobo, exhorting the audience to be "Traitors never, loyal always," televised images showed.

The military is planning larger exercises on Feb. 10-15, which Maduro said would be the "most important in the history of Venezuela."

Maduro was elected in May last year with 67.84 percent of the votes, and he was sworn in as president on Jan. 10 for another six-year term. On Wednesday, Guaido, 35, declared himself interim president.

As tensions between Maduro and Guaido continue, officials and experts worldwide have voiced concern over the situation, calling for dialogue to ease tension without outside influence.

United Nations Secretary-General Antonio Guterres has urged all relevant actors to lower tensions and commit to dialogue to address the protracted crisis in Venezuela, after anti-government protests in the capital Caracas turned violent, said his spokesman on Thursday.

Echoing Guterres' call for a dialogue, Alfred-Maurice de Zayas, a former UN independent expert, termed the current unrest as an "attempted coup" and said his concern is to avoid a civil war.

China believes that Venezuela's affairs must and can only be decided by the its own people, a Chinese Foreign Ministry spokesperson said Friday.

China maintains that all countries should adhere to the purposes and principles of the United Nations Charter, especially the norms of international relations and international law, such as non-interference in each other's internal affairs, mutual respect for sovereignty and territorial integrity, and refraining from the threat of force, spokesperson Hua Chunying told a press briefing.