WASHINGTON (Reuters) - The United States imposed sanctions on another son of Nicaraguan President Daniel Ortega, Rafael, on Thursday, accusing him of money laundering and corruption, in the latest effort by Washington to put pressure on the leftist government.

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The Trump administration has accused the current Nicaraguan government of concentrating power in the hands of the president and his wife, Vice President Rosario Murillo, who is already subject to U.S. sanctions along with other Nicaraguan officials.

The Trump administration has also criticized the government for cracking down on anti-government protests and accused it of human rights abuses, unlawful killings, arbitrary detentions, political persecution and widespread corruption.

The U.S. Treasury Department blacklisted two of Rafael Ortega’s companies that it said he used to launder money for and finance the Ortega government, as well as a third company controlled by the family.

It said Rafael Ortega, the second Ortega son to be blacklisted by the United States, was targeted under an executive order for providing support to Murillo, who was blacklisted last year.

“Rafael Ortega is the key money manager behind the Ortega family’s illicit financial schemes,” Treasury Secretary Steven Mnuchin said in a statement.

Nicaragua has been gripped by a political crisis since early 2018 when demonstrations broke out against Daniel Ortega, a Cold War-era U.S. foe and former guerilla leader, over planned cuts to welfare benefits.

The demonstrations have since grown into a broader protest movement, and more than 300 people have been killed by police or armed government-affiliated groups, rights groups say.

U.S. Secretary of State Mike Pompeo called on the government “to resume dialogue with the opposition and restore democracy in the country.”

“Nicaragua’s painful political crisis can only be resolved through free and fair elections that credibly reflect the will of the Nicaraguan people,” he said in a statement.

The latest sanctions freeze any U.S. assets of Rafael Ortega and the targeted companies and bar Americans from doing business with them.

Washington is accusing Rafael Ortega of using his company Inversiones Zanzibar, S.A., as a “front company” to avoid U.S. sanctions and said his security firm Servicio De Proteccion Y Vigilancia, S.A., had received numerous government contracts.

A chain of gas stations, Distribuidor Nicaraguense de Petroleo S.A. (DNP), which was bought with public money before being transferred to the Ortega family, had benefited from non-competitive contracts with the government, the U.S. Treasury said.

DNP controls about a third of Nicaragua’s fuel sales, according to statistics from the Ministry of Energy and Mines.

Rafael Ortega and the Nicaraguan government did not immediately reply to requests for comment on the new sanctions.

Managua has called U.S. sanctions on officials a continuation of “imperial” designs on the small Central American country.