Saudi Arabia declared tonight that it will support a Middle East peace treaty only if it includes all of Israel's Arab adversaries and guarantees self-determination and statehood to the Palestinian people.

The official statement, relayed by the Saudi News Agency after a meeting of the royal Council of Ministers, indicated that the kingdom remains firmly opposed to the Egyptian-Israeli treaty sponsored by the United States and scheduled for signing next week. It came one day after the departure of U.S. national security adviser Zbigniew Brzezinski, who visited Riyadh and Amman in an attempt to contain Saudi and Jordanian opposition to the pact.

Saudi support for the treaty -- or at least a lack of active opposition to it -- is considered important by U.S. policymakers because the wealthy oil kingdom gives about $1.5 billion a year in vital aid to Egypt and its Persian Gulf allies supply another $500 million.

After the council meeting, run by Crown Prince Fahd. Information Minister Mohammed Abdo Yamani issued a declaration that seemed designed to suggest the Saudis are considering a reduction in the aid. It said:

"We are fully convinced that all resolutions aimed at solving the [Middle East] problem must be in the context of decisions made by Arab summit conferences. As such, we are committed to these resolutions and are keen on implementing them, as our goal is to reach a just and lasting peace based on right."

This appeared to be a reference to the Arab summit conference last November in Baghdad, at which the Saudis were reported to have aggreed to anti-Egyptian measures to be put into effect if Egypt signs a separate peace treaty with Israel. These measures were said to include an aid cutoff or reduction, boycott and removal of Arab, League headquarters from Cairo.

Since the Egyptian-Israeli accord was reached last week, however, the Saudis have hinted that the aid will continue at least for the time being. Fahd told an interviewer that Saudi relations with Egypt were based on more than one consideration and observers noted that tonught's declaration also left plenty of room for interpretation.

The Egyptian defense minister, Kamal Hassan Ali, predicted in Washington that Saudi aid will continue for the immediate future while the kingdom judges whether the Egyptian-Israeli treaty stands any chance of leading to a broader accord that would include the Palestinians.

The Jordanian monarch, King Hussein, is expected to follow Saudi Arabia's lead. His decision also is considered crucial, since the Camp David frame work envisions Jordanian participation in negotiations over Palestinlan autonomy in the Israeli-occupied West Bank.

Elsewhere in the Arab world, Iraqu Vice President Saddam Hussein predicted that Egyptian President Anwar Sadat will "face the same destiny faced by the shah of Iran."

"Sadat believes that he possessed the universe when [President] Carter put his arms around him, but he forgets that he who is 'apping on his should is putting an end to him and creating a wide gap between Sadat and the Egyptian people," Hussein said in a speech reported by the Iraqi Information Ministry.