Syria has intensified its political and military pressure on the Palestine Liberation Organization by moving against its offices and training camps in this country, informed sources said here today.

While relaxing its ring of tanks and mortars around the Palestinian camps in Beirut last week, Syria closed the PLO's military training facilities here. At the same time it banned the Palestinian guerrillas from carrying light arms - automatic rifles - in their offices in Damascus.

"They are trying to disarm us," said one Palestinian fighter guarding the Damascus office of Fatah, the largest and best-trained of the PLO commando groups.

He was carrying no weapon today; two weeks ago he stood just inside the office door cradling a Kalashnikov, a Soviet-made automatic rifle favored by the Palestinians.

The moves against the PLO here are part of a concerted Syrian effort to tame them so they will not block the Arab powers' drive to achieve a settlement.

The mainstream Palestinians, facing the superior might of the Syrian army in Lebanon and here, have decided to give in to the pressure little by little.

"We think that if we play it smart and go along with their silly little games we can survive," said a PLO executive committee member in Beirut.

"We think we are stronger than the Arab regimes," he added, voicing the familiar PLO theme that at least one of the pressuring Arab states - Egypt and Syria - is liable to collapse before they succeed in subjugating the Palestinians.

Egypt has massive internal economic problems, as shown by last month's food riots, but most observers here believe that Syrian President Hafez Assad is firmly in control of this country and there is little chance that he will be overthrown in the near future.

The Syrian action against the Palestinians in Lebanon is serving a dual purpose, according to observers here. At the same time the Syrian forces are pressuring the Palestinians to take a more moderate stand in preparation for peace talks, they are achieving their goal of collecting all heavy weapons in Lebanon.

"The Syrians are determined to see through the disarmament of Lebanon," said one well-informed observer here. "Everyone is being made to give up their weapons - the Palestinians, the Christians, the Druze," a left-wing Moslem sect.

Sources here say the Syrians have let it be known that they do not care whose heads they crack while getting these weapons.

While they have raided some rightist Christian arms caches, the major part of their efforts up to now has been against the Palestinians. The Syrians are going first for weapons they know are stored in the Palestinian camps in Beirut. But most of the Palestinians' weapons - including crates of unused guns and ammunition and dozens of new armored cars - are stored in depots in southern Lebanon.

The Syrians cannot go after those store-houses now because of Israeli pressure against their entering southern Lebanon.

The Syrian pressure has already moderated the PLO's position on formation of a Palestinian state.

Although no official announcement has been made, the PLO leadership has been sending clear signals for the past three months that it has retreated from the dream of replacing the Jewish state of Israel with a secular Palestinian nation.

Instead, the Palestinians - with the exception of the extremist "Rejection Front" organizations that still oppose any settlement allowing the existence of Israel - are now willing to settle for a palestinian state on the West Bank of the Jordan River and the Gaza Strip, land now occupied by Israel.

Syria, Egypt and Saudi Arabia have succeeded in enlarging and stacking the Palestinian National Council, the partiament in exile, which is scheduled to meet in Cairo next month. The aim is to force changes in the Palestinian national convenant so that it will no longer call for an end to the state of Israel.

The Arab powers believe that changing that provision will go a long way toward removing Israel's stated objections to sitting at a conference table with the Palestinians.

But, according to sources here, the Syrians are reluctant to go much further in taming the Palestinians unless Israel makes similar concessions.

News agencies reported these other Middle East developments:

Foreign Minister Yigal Allon of Israel called a recent statement by President Anwar Sadat of Egypt dealing with relations between Jordan and the proposed Palestinian state a step in the right dorection. Sadat last week called for a "confederal link" between Amman and the Palestinian state.

King Hussein of Jordan and French Foreign Minister Louis de Guiringaud conferred in Amman about current diplomatic moves in the Middle East.