U.S. civil rights leader Jesse Jackson said today the Palestine Liberation Organization had seized the moral initiative by declaring a cease-fire in southern Lebanon.

But Western diplomatic sources said a statement by the PLO which included the cease-fire pledge fell short of any major policy changes.

In Jerusalem, Israeli officials expressed skepticism about the statement. "This is not the first time we have heard such promises," a Foreign Ministry source said.

Official sources said the Israeli Cabinet might comment at its next meeting but no official statement would be made at present.

Jackson flew home to the United States today after a personal diplomatic initiative in the Middle East aimed at putting pressure on the United States to open talks with the PLO.

The PLO document was a step toward a dialogue with the United States, Jackson said. The document did not make clear whether the PLO would halt seaborne raids on Israel from Lebanon. But PLO spokesmen said it was different from a U.N.-mediated truce in the area because it was being declared by the Palestinians alone.

The statement did not change any of the PLO's basic positions, but Jackson argued it had "clarified" many aspects of the Palestinian issue.

The statement:

Called for establishment of an independent Palestinian state "on any part of Palestine evacuated by the Israelis";

Reaffirmed the PLO's rejection of the Camp David accords which led to the Egyptian-Israeli peace treaty;

Claimed the United States "neglects" Palestinian rights while it gives support to Israel;

Challenged what is called an inaccurate "Zionist propaganda campaign" that the PLO wanted to "exterminate" Jews;

Called for increased international support for the Palestinian cause.