NORTHERN SAUDI ARABIA -- The Saudi commander stepped to a microphone in the desert to address probably the best trained -- and certainly the most experienced -- soldiers in his combined Arab forces arrayed against Iraq.

"Thank God," said Lt. Gen. Khalid bin Sultan, "the Syrian people did not believe" Iraqi President Saddam Hussein's claim that occupying Kuwait "is the way to liberate Palestine" from Israel.

About 900 Syrian troops, part of a 15,000-man armored division sent to the U.S.-led multinational force by President Hafez Assad, gave the Saudi general enthusiastic applause and then showed him what their Soviet-made T-62 tanks can do.

This display of solidarity came as Khalid, a Saudi prince, said that Iraq has increased its troop strength by "a few divisions" along the Saudi-Iraqi border in the last two weeks. The new Iraqi deployment, which could involve up to 45,000 men, reportedly is just west of the Saudi-Kuwaiti border, where Iraqi troops have been since their invasion of the emirate Aug. 2.

A Saudi official said last week that before there can be a negotiated solution to the Persian Gulf crisis, Iraq must withdraw its forces from the Saudi-Iraqi border. This had not been a condition declared previously for talks between Saudi Arabia and Iraq.

The new military alliance between Saudi Arabia and Syria, which Khalid sought to demonstrate on a visit Saturday to Syrian camps, is limited. But it is among the twists in Arab politics set off by Iraq's invasion of Kuwait.

For more than two decades, Riyadh and Damascus have been at opposite poles of the Arab world. Dominated by the secular Baath Arab Socialist Party, Syria has been a close ally of the Soviet Union. Saudi Arabia is a conservative, religious Moslem monarchy aligned with the United States.

While Damascus has sought to undermine the leadership of Palestine Liberation Organization Chairman Yasser Arafat by supporting his Palestinian rivals, Saudi Arabia has poured billions into PLO coffers.

Just last year, Saudi Arabia was critical of Syria's role in Lebanon, where up to 40,000 of its troops were stationed. It took a cutoff in Saudi Arabia's annual financial subsidy to the hard-pressed Syrian economy to win Assad's acceptance of the 1989 Saudi-brokered Taif Accords, which were aimed at reviving Lebanon's government and restoring its independence.

And even though Assad, who considers Saddam his most dangerous rival, quickly joined the anti-Iraq coalition in August, he committed a substantial number of troops to the multinational force only after hefty payments from Saudi Arabia. In addition to $1 billion in immediate aid, half of it in cash, the Saudis promised to resume annual aid payments, a Saudi official said.

Khalid said Syria has sent the armored division it promised, a unit of about 15,000 men and 300 combat vehicles, including the T-62 tanks. In addition, about 2,000 Syrian special forces are here.

Sporting skull-and-crossbones badges, these special forces showed Khalid their prowess. Wearing gas masks and crouching in newly dug trenches, they staged a mock defensive action against a tank attack.

The commander of Syrian troops here, Maj. Gen. Ali Habib, would not speak to reporters and when individual Syrian soldiers approached journalists to chat, they were ordered away by superiors.

Despite the display of cordiality between Khalid and Habib, some diplomats said the Saudis have reservations about the Syrians' presence. "The Saudis are worried about them," one diplomat said. "They don't trust them."

Khalid, asked about speculation that the Syrians might refuse to fight Iraqis, said such reports "are not true. I can assure you."

In his remarks to the Syrians on Saturday, Khalid appeared eager to address reservations they might have about fighting Iraqis. "We are not against the Iraqi people," he said. "We would stand beside Iraq in the same way if it were subject to aggression. We are not against the Iraqi armed forces . . . but if their leader misuses them, then we have no option but to stand against him and fight his forces."

Below him, the Syrians had spelled out their own sentiments in a row of stones placed in the sand which read: "God is great. We come to you, and are part and parcel of you. Victory to the Arab nation."