A full-page advertisement that used the names of six humanitarian agencies to denounce "the Israeli invasion of Lebanon" was placed in The Washington Post and other major newspapers last week without the knowledge of the groups involved, according to spokesmen for the organizations.

The ad was placed "outside the jurisdiction" of the advertising agency whose employe forwarded payment for the ad, agency president Bernard Hodes said.

In a letter to the editor, the organizations said they were "dismayed" at being listed and "respectfully decline any association" with the ad, signed by "Concerned Americans for Peace" listed at a Los Angeles post office box number.

The letter was signed by executives of CARE, the U.S. Committee for UNICEF, the Church World Service of the National Council of Churches, the American Red Cross, the American Friends Service Committee and the Save the Children federation. Their letter said taking any political stand would jeopardize their humanitarian work.

Virginia Rodriguez, speaking for The Washington Post, said the $26,420 ad was placed by the Bernard Hodes agency in Los Angeles, which provided a standard industry form in which the client, Concerned Americans for Peace, certified that the six groups had given permission. The form was signed "Craig," followed by a semi-legible last name, on behalf of the client, Rodriguez said.

Agency president Hodes said The Post ad, published July 11, was "placed out of channels" by Pat Howard, branch manager of Hodes' Los Angeles office, who used Hodes' stationery in forwarding payment for the advertising in the form of cashier's checks made out to the newspapers.

Apart from that, Hodes said, the firm had not handled any money or paper work for the ad, also published in The New York Times, the Atlanta Journal-Constitution and the Chicago Tribune.

"Obviously Mr. Howard was used," Hodes said. "I'm personally furious, and Pat is a nervous wreck, very upset. . . . The question is, who's behind this?" He could not identify the purported signer of the standard form, and Howard was unavailable for comment.

Hodes criticized the newspapers that published the ad for not checking further. He said the Los Angeles Times, unable to verify that the organizations endorsed the ad's viewpoint, ran it without the groups' names, and that the Christian Science Monitor refused it altogether.