CAIRO, AUG. 16 -- The only army involved in the tense Persian Gulf confrontation other than Iraq that has used chemical weapons in actual combat is Egypt's, and senior Egyptian military officials say they are "completely prepared for any eventuality."

"We have had lots of training with this kind of equipment in the desert area, and we are not worried. The problem is to have sufficient early warning," a senior army intelligence official said this week.

The official acknowledged that Egyptian troops that were sent to Yemen as part of the erstwhile United Arab Republic's expeditionary force during the 1962-69 civil war used chemical weapons against royalist forces.

In January 1967, when Egypt had an estimated 80,000 troops in Yemen supporting the republicans against the Saudi Arabia-backed royalists, the Egyptian-dominated U.A.R. forces were accused of using poison gas. However, until now, Egypt refused to acknowledge it.

Officials still refuse to confirm reports that they have facilities for manufacturing chemical weapons.

The military official, who spoke on the condition that he not be identified, said most of the Egyptian troops involved in the Yemen conflict were of a previous generation. He said, however, that the army has maintained its proficiency in chemical warfare and has drawn on its battle experience.

Referring to reports that Iraq has moved chemical weapons into the Kuwaiti-Saudi border region, the military official said, "The Iraqis know if they use it, it will be used against them. Also, there are other means." He would not be specific about what means he had in mind.

Iraq used chemical weapons extensively in its eight-year war with Iran, mostly before mounting major offensives against positions in which Iranian forces were deeply entrenched. It used nerve gas against Kurdish rebels in northern Iraq. Iran, not engaged in the current crisis, also used chemical weapons in the Iran-Iraq war.

Military officials here stressed that the deployment of Egyptian troops -- mostly commandos -- to Saudi Arabia is primarily defensive, to help Saudi Arabia protect vital military installations and oil fields in the northeastern part of the kingdom from possible Iraqi aggression.

A Defense Ministry source said 2,000 more Egyptian soldiers left Cairo for Saudi Arabia today to join the 3,000 already there. The source said further airlifts would depend on developments in the gulf and on Saudi requests.

The senior officer said joint U.S.-Egyptian training exercises, called "Operation Bright Star," which have been conducted every other year in the Egyptian desert since 1981, could prove to be useful in the current confrontation only if joint ground operations became necessary.

"But now, this is not the case. It is not a joint American-Egyptian operation. Our mission is separate from the American forces. We are working under the Saudi Arabia military command to defend their installations against attack," he said.

He said he thought that Iraqi President Saddam Hussein may be repeating the mistake he made during the war with Iran -- failing to think through his final objective before attacking.

"When you think about waging a war, you have to think in the beginning where you will end, according to your political objectives. In the war with Iran, he didn't think where it would end. Does he think that annexing Kuwait will be accepted by the world? Does he think he can defeat the United States and the whole international community?" the official asked.

He said that from a military standpoint, the wisest thing for Saddam to do now would be to put his forces in a defensive mode on the Saudi border and dig in for shelter. "To attack him, you would need to amass forces of 2-to-1, minimum. At that ratio, you need a minimum of 500,000 soldiers."

A senior official in Mubarak's government, who is a civilian, said the number of Egyptian and other Arab forces that are deployed in Saudi Arabia is relatively unimportant because their primary mission is to protect air bases from which U.S. warplanes would carry the brunt of any retaliation against Iraq..

If hostilities break out, the official said, the Iraqis are likely to be stunned by the swiftness and intensity of the air strikes.

"They fought a primitive battle with the Iranians and think they are experienced, but they aren't. The same thing happened to us in Yemen. We thought we were good, fighting this prehistoric kind of warfare. But then came 1967, and we realized the effects of modern arms," the official said, referring to the 1967 war with Israel.