Syrian Foreign Minister Abdul Halim Khaddam said yesterday that hardline Arab nations will have to "make military pacts with the Soviet Union" if Israel signs a defense treaty with the United States.

Khaddam, on a tour of leftist Arab countries, is coordinating efforts by militant Arab governments to counter any agreement that might come out of President Carter's Camp David summit with President Anwar Sadat of Egypt and Prime Minister Menachem Begin of Israel, Damascus radio reported.

He said in Algiers that the Camp David meeting is "a link in a chain of plots against the Arab nation." A summit of the Arab "steadfastness front" is necessary to agree on new strategy, he told reporters.

Syria, Libya, Algiers, South Yemen and the Palestine Liberation Organization make up the front, formed in Tripoli last December to counter Sadat's peace initiative with Israel.

Khaddam was in Moscow last week to discuss the Camp David talks. Syria is one of the biggest recipients of Soviet arms in the Arab world and the other front members also have close military ties with Moscow.

"Arabs should mobilize themselves and make military pacts with the Soviet Union if current efforts to conclude an American-Israeli mutual defense pact are realized," Khaddam said.

Meanwhile. The Lebanese education minister said in Beirut that security conditions are so bad in Lebanon that yearend examinations have been postponed indefinitely.

"Examination monitors are frightened," said the minister, Assaad Rizk. "Almost all zonal supervisors complained they will not be able to hold the examinations on time because of menacing security conditions."