U.S. special Middle East mediator Philip C. Habib flew here today to meet with senior Syrian officials in a fresh effort to find a basis for agreement on the withdrawal of foreign military forces from Lebanon.

The U.S. envoy, who returned to the Middle East last week, arrived in Damascus amid a spate of official criticism of Washington's role in the Middle East that cast new doubts on U.S. optimism about reaching an accord for the withdrawal by the end of the year of Israeli, Syrian and Palestine Liberation Organization (PLO) troops.

Accompanied by his deputy, Ambassador Morris Draper, Habib met with Syrian Foreign Minister Abdul Halim Khaddam for 2 1/2 hours this morning. Neither the U.S. delegation nor Syrian officials commented on the talks or indicated whether -- as Washington clearly hoped -- Habib would be meeting with President Hafez Assad before his departure Thursday.

Western diplomats here in touch with senior Syrian government officials were not optimistic about Habib's chances of making progress with the Syrians on troop withdrawal before he had nailed down an Israeli withdrawal timetable.

Habib is here on his first visit to Syria since the conclusion last August of an accord that led to the evacuation of PLO fighters and their Syrian Army allies from Beirut, the Lebanese capital.

The Syrian view of Habib's mission was restated this morning in an editorial in the government newspaper Tishrin. "Nothing can change the fact that Habib will not make any great effort in Lebanon towards the preservation of Lebanese sovereignty," the editorial stated. "He is only working in the service of America's strategic interest, and this interest is governed by nothing more than the higher strategic interest of Israel."

The editorial was among a series of hard-line Syrian statements apparently orchestrated for Habib's return to Syria.

Last Saturday, in a speech marking the 12th anniversary of his coming to power, Assad strongly attacked U.S. policy in the Middle East and delivered a thinly veiled criticism of President Reagan's Sept. 1 Middle East peace proposal.

While Assad did not mention the Reagan plan by name, he left no doubt of his own disdain for it. "Attempts are being made now to drag the Arab nation into capitulatory negotiations under the label of peace," Assad said. "And what is required of the Arabs thereunder is to waive our rights even before the required negotiation starts."

Assad repeated the Syrian position that there can be no agreement for a troop withdrawal of the estimated 30,000 Syrian troops in Lebanon until Israel withdraws first. He accused the United States of acting as "a lawyer for Israel, adopting every Israeli wish, conniving -- if not defending -- any Israeli aggression." President Assad explained how Syrian troops in Lebanon had gone there at the request of the Lebanese government in 1976 to put an end to Lebanon's 18-month-old civil war. He said that they had remained there at the pleasure of the Lebanese government as an Arab peace-keeping force under the mandate of the Arab League.

Because of this, he said, Syria's troops should not be placed on the same basis as those of Israel's. He said it was up to the Lebanese government, not a U.S.-mediated agreement, to request the nations to pull out of Lebanon. To date, he said, no such official request had been made.

Assad, however, said that if Israeli forces withdrew from Lebanon without forcing any conditions such as a peace treaty on the Lebanese government "there would be no problem concerning our forces."

"Nothing is going to happen this year that we can see from here," said a European ambassador here. "The troops in Lebanon, everyone's, are there for the winter at least, if not longer."