BEIRUT, OCT. 22 -- The pro-Iranian Islamic Jihad organization warned today that thousands of martyrs are waiting to launch suicide missions in the Persian Gulf region, hinting that the United States' vulnerability in confronting Moslems will be demonstrated within days.

On the eve of the fourth anniversary of the twin truck bombings of the Beirut headquarters of U.S. Marine and French peace-keeping troops, the group delivered a typewritten communique to the offices of a western news agency, accompanied by photographs of American hostage Terry Anderson and missing French journalist Jean Paul Kauffmann. The statement made no reference to the hostages.

"The next few days will expose to the world the true dimensions of American strength in confronting Moslems," the statement said. "Only the cowardly rulers in the region have illusions about . . . this paper-thin capability."

Enclosed with the statement were color photographs of the Marine and French headquarters before they were bombed, two minutes apart, killing 241 American and 58 French servicemen.

"There are thousands of the likes of our martyrs in the gulf today awaiting the right moment to recreate the glory of Moslems and Islam," the Iranian-backed group warned.

Its statement came two days after Tehran vowed to avenge Monday's U.S. attack on an Iranian oil platform in retaliation for a missile that hit a U.S.-flagged Kuwaiti tanker.

After the 1983 bombings in Beirut, Islamic Jihad said, all the United States could do was "gather the limbs of its soldiers and flee from the fists of Moslems in Lebanon."

"We have eliminated the heads of American intelligence in the area, and our determination to strike again at the proper time and place is still firm," it added. Islamic Jihad previously had announced the execution of William Buckley, the CIA station chief in Lebanon, after his kidnaping in March 1984.