Deputy Secretary of State Robert B. Zoellick, stepping into a political crisis, met a onetime Sandinista loyalist Wednesday to press U.S. influence in this divided Central American nation.

The discussion with former Managua mayor Herty Lewites, now a critic of his former allies, was part of an effort to thwart what Zoellick called a "creeping coup" by Sandinista leader Daniel Ortega and former president Arnoldo Aleman.

During a two-day visit to Managua, the capital, the State Department's second-ranking official has piled pressure on Sandinista and rightist opposition leaders whom the Bush administration accuses of undermining President Enrique Bolanos, a U.S. ally.

Zoellick announced earlier that the United States had revoked visas held by Nicaragua's attorney general and Aleman's two adult children, and threatened to withhold millions of dollars in aid.

The renewed U.S. interest in Nicaragua, where the Reagan administration supported rebels known as contras against Ortega's government in the 1980s, angered the opposition. "We protest to the world about the U.S. government's unwarranted interference in the internal affairs of our country," Aleman's party said in a statement.

Zoellick this week described an informal alliance between the Sandinistas and Aleman, who is restricted to the capital after being convicted of corruption during his 1997-2002 rule, as a "corrupt pact."

The alliance already controls the judicial and legislative branches of government, and the conflict has at times threatened to force Bolanos from office.

U.S. officials have expressed concerns that Ortega, whom the U.S. government accused of running a Soviet-backed government during the Cold War, could return to office when elections are held next year.

Zoellick met Tuesday with Eduardo Montealegre and Jose Alvarado, both of whom are considering running for president. He also met leaders of the Movement for Nicaragua, which has organized pro-democracy demonstrations.

Deputy Secretary of State Robert B. Zoellick greets girls in traditional dress during his visit to a school in Managua, where a political crisis is brewing.