The Iraqi military has built a 150-mile "obstacle belt" of mines, wire fences and tank traps across occupied Kuwait, and its tanks are so well dug into the desert that aircraft will have a difficult task locating Baghdad's armored legions, officials said.

British Defense officials, who gave a briefing Wednesday on condition of anonymity, said by mid-November, American, British and allied Arab forces would have in their theater a formidable array of air power but would still be outnumbered by the ground forces of Iraqi President Saddam Hussein.Within two weeks, they said the U.S.-led multinational force now numbering 256,000 personnel would have about 1,600 tanks, 750 artillery pieces, 310 attack helicopters and some 1,110 combat aircraft.

Iraq, which invaded Iraq on Aug. 2, now has about 390,000 troops in and around Kuwait, along with 3,600 tanks, 2,300 artillery pieces, 125 attack helicopters and about 800 combat aircraft, the officials said.

Elsewhere, the commander of the British forces in the gulf, Air Chief Marshall Sir Patrick Hine, said upon returning to Britain that "it was looking increasingly unlikely" that Saddam would withdraw from Kuwait.

He said the British forces "were devoting more time to the question of how we would fight," and that by mid-November, Britain "would be ready to fully support offensive operations should the political decision be taken."

In the briefing, the officials gave a sober analysis of the prospective conflict with Iraq, declining to speculate on how many casualties would be sustained among the British forces - which will number 16,000 within two weeks - but offering no illusions that combat would be easy or bloodless.

"If we had to be pushed into war, the allies would try not to make it protracted," one of the senior officials said. "We have to live with the situation afterward. We would have to do it as clinically and as efficiently as possible."

They said the Iraqi military had placed itself in three defense echelons.

Just across the border inside Kuwait, the Iraqis have constructed an "obstacle belt" of minefields, tank traps, ditches and barbed wire.

The barrier spans some 150 miles from the gulf waters to the Iraqi-Kuwaiti border in the west.

"The longer that they are there, the better these defenses will become," one official said.

Saddam has placed a reserve force, mostly of crack revolutionary guards, astride the Kuwaiti border. Analysts believe he is aware the loss of his most competent soldiers could cause the military command to collapse, so he has shrewdly kept them away from areas that would presumably bear the brunt of multinational air power.

But the officials stressed that multinational pilots had a potentially difficult task.

"Ground forces that are dug in don't present a very good target from the air," one high-ranking official said. "That would be quite difficult.