A coalition of activist human-rights organizations called on Congress yesterday to cut off or drastically reduce U.S. military aid to 13 countries the coalition says abuse the rights of their citizens.

The coalition was especially critical of the Carter administration's plans to continue military assistance and sales to Iran, the Philippines, Nicaragua and Indonesia.

By justifying aid to these countries on the grounds that they are important to U.S. national security, the coalition said, the administration runs the risk of undermining the credibility of its own championing of human rights.

The organization, the Coalition for a New Foreign and Military Policy, is composed of liberal church, political and other groups active in the human-rights field.

The other targets of its criticism were Bangladesh, Bolivia, the Dominican Republic, Haiti, Morocco, Paraguay, South Korea, Thailand and Tunisia. It made public its "critiques" of the human-rights status reports prepared recently by the State Department on these 13 countries.

The reports were commended for showing"vast improvements" over the departments" over the department's efforts the previous year, but the coalition said they still are marred by omissions, distortions and misleading information that appear aimed at portraying the governments of the 13 countries in the best possible light.

In a letter to Sen. John J. Sparkman (D-Ala.), chairman of the Senate Foreign Relations Committee., the coalition said the department had "a tendency to underestimate the number of political prisoners and the frequency of torture and other cruel punishment."

It added: "We believe that a reduction or termination of military aid and sales to all 13 of these countries is justified."n the administration's military aid proposals for the 1979 fiscal year, the only country marked for a significant cutback of military aid is Nicaragua. As the coalition noted, the other are slated to continue receiving assistance or the right of purchase U.S. weaponry at roughly the same levels as in past years.

At a press conference yesterday, coalition leaders promised a vigorous effort to lobby Congress in pursuit of aid reductions to these countries. Rep. Thomas R. Harkin (D-lowa), who has sponsored several human-rights amendments in recent years, appeared at the press conference to pledge his support in this drive.

Among the organizations participating in the coalition are Americans for Democratic Action, the United Methodist Church, United Church of Christ, Friends Committee for, National Legislation, the National Coluncil of Churches, the Washington Office on Latin America and Clergy and Laity Concerned.