JERUSALEM, JUNE 18 -- Prime Minister Yitzhak Shamir invited Syrian President Hafez Assad today to open peace talks with Israel and criticized the United States for delaying a decision on whether to continue contacts with the Palestine Liberation Organization.

Appearing before high school students in the town of Petah Tikva, Shamir expanded on one of the principal public stances of his new right-wing government by calling on Assad "to come, to talk, to conduct negotiations and maybe to get to peace." Shamir also issued the invitation in an interview published today in an Egyptian newspaper.

Shamir expressed impatience at the slowness of the Bush administration to decide on whether to break relations with the PLO as a result of the attempted attack by guerrillas of the PLO-affiliated Palestine Liberation Front on Israeli beaches May 31. "Week after week passes, and they are still discussing, there in the diplomatic offices in the United States, if the PLO is a terrorist organization," Shamir said. "And they can't decide."

The Bush administration, Shamir added, "has to prove the credibility of the United States, to prove to the whole world that those who engage in terror cannot be party to negotiations."

Shamir's remarks, which came a week after parliament voted approval of his new coalition, underlined the two initial strategies the government has adopted in its approach to the stalled Middle East peace process. Blamed by Washington for his refusal to accept a proposal for Israeli-Palestinian negotiations, Shamir is seeking to ease the pressure on his country by directing attention to another issue, the state of relations between Israel and the Arab states, and by pressing for a break in relations between the United States and PLO.

Leaders of Shamir's Likud Party have long sought to persuade the United States to halt contacts with the PLO, arguing that a new Palestinian leadership must be found or created in the occupied territories for peace talks to proceed. However, leaders of the left-wing Labor Party have said a break in U.S.-PLO relations would set back the peace process, which they contend is dependent on PLO cooperation.

Secretary of State James A. Baker III told a congressional hearing last week that the Bush administration is considering ending the dialogue with the PLO because of the May 31 attack but will not be rushed into a decision. Washington has said the PLO must condemn the attack and take action against the faction that organized it, but the PLO's leadership has so far refused to comply.

Formally, Shamir's proposal for peace talks between Israel and Arab countries dates to the peace initiative he launched in May 1989. Until now, however, both the Bush administration and the previous "unity government" of Shamir focused on the initiative's plan for the election of Palestinian representatives to negotiate with Israel for self-rule in the occupied West Bank and Gaza Strip.

The U.S. view has been that it is unrealistic to expect the opening of relations between Israel and Arab countries such as Syria, Jordan and Iraq until Israel advances toward a compromise with the Palestinians in the occupied territories. For that reason, Shamir's new public emphasis on peace talks between Israel and Arab countries is seen by government critics and some diplomats here as more an attempt to deflect criticism from his new administration than a serious diplomatic move.