Four senators yesterday introduced legislation urging the administration to end its dialogue with the Palestine Liberation Organization for refusing to condemn a thwarted guerrilla attack on Israel by one of the PLO's constituent groups.

The move coincided with a PLO statement from its Tunis office excoriating the United States for "protecting Israel and its crimes . . . and encouraging it to commit more." Distributed by the official Palestine News Agency, the statement followed an acrimonious and inconclusive two-day meeting of the PLO's 15-member executive committee in Baghdad that U.S. officials had been watching closely for signs of PLO action to condemn the attack.

The lack of any PLO disciplinary action against hard-liner Mohammed Abul Abbas, whose group claimed responsibility for the assault, was "discouraging," a U.S. official said.

In an escalation of pressure by Israel's supporters for strong U.S. action, Sen. Connie Mack (R-Fla.) joined Sens. Joseph I. Lieberman (D-Conn.), Frank R. Lautenberg (D-N.J.) and Charles E. Grassley (R-Iowa) in calling for an immediate suspension of the U.S. dialogue with the PLO that began in December 1988 after the PLO renounced terrorism.

"Either Yasser Arafat is the leader of the PLO, or he isn't. If he is, he must demonstrate leadership and prove he has control by condemning the actions of the Palestine Liberation Front. If he isn't, then we have no business dealing with him," Lieberman said yesterday.

The PLF launched an aborted seaborne guerrilla attack against an Israeli beach May 30, saying afterward it was intended to avenge the slaying of seven Palestinian laborers by a deranged Israeli 10 days earlier.

Arafat distanced himself from the PLF operation, saying the PLO's "institution and official forces" had no connection with the attempt. He said he saw "no reason" for the United States to halt its dialogue with his organization.

Palestinian sources in Washington said Arafat chided Abul Abbas at a stormy meeting in Baghdad for stepping out of line at this critical juncture, but had found "no support" for more radical measures against him because of deep dissatisfaction among other PLO factions with the lack of progress in U.S. efforts to obtain concessions for peace from Israel.

Middle East experts here said Arafat will not be able to justify the expulsion of Abul Abbas, who was elected to the executive board by the Palestine National Council, the Palestinian parliament in exile, at a time of growing militancy and unrest in Israeli-occupied territories. They also reported a growing feeling that PLO preoccupation with the political process is out of touch with the reality of the Palestinian uprising there.

The National Association of Arab Americans, a Washington-based lobbying group, joined in condemning the attack. It "can do nothing to achieve progress towards an independent state but only strengthens the hand of Israeli hard-liners," said association executive director Jawad F. George. He said ending the dialogue would "empower the extremists by giving them a veto power over the process."

On June 1, 33 senators signed a letter to Secretary of State James A. Baker III urging the administration to call on Arafat to "unequivocally denounce the attempted terrorist attack on Israel by the Palestine Liberation Front, and to expel Abul Abbas from the PLO's executive committee."

Yesterday the four senators charged that the PLO had violated its commitments, noting that the "United States is obligated . . . to cease all contact with the PLO until the PLO's adherence to said commitments is fully and fundamentally demonstrated. . . . "

One official said Baker alone has authority to make a final pronouncement on the fate of the dialogue, once he returns from a meeting in Scotland of foreign ministers of the North Atlantic Treaty Organization. "It's both unfortunate and incomprehensible that they {the PLO} should issue such declarations" as the one from Tunis, the official said.