The international commission monitoring compliance with a Central American peace accord has said that an end to U.S. aid for the Nicaraguan rebels is an "indispensable requirement" for the success of the pact, according to a copy of its report distributed here yesterday.

The strong criticism of U.S. support for the contras is contained in the final report prepared by the International Verification Commission for the five Central American presidents who are meeting today in San Jose, Costa Rica. The Center for International Policy made the copy available.

The commission went on a week-long tour of Central America last week to gather information for its report, completed yesterday in Panama.

"In spite of the exhortation of the Central American presidents, the government of the United States maintains its policy of providing assistance . . . to the irregular forces operating against the government of Nicaragua. The definitive end to this assistance continues to be an indispensable requirement for the success of the peace efforts," the report said.

The United States was the only government outside the region singled out for censure in the report.

The commission includes top diplomats from the five Central American countries and eight Latin American nations, plus representatives from the United Nations and the Organization of American States.

The commission also pressed to be allowed to make on-site inspections in the different countries to assess their compliance on security issues and recommended an extension of the accord deadlines with fixed new timetables and tasks for each nation to meet.