US B-52 bomber planes and F117 stealth fighters have been ordered to the Gulf region as part of a build-up in forces after Iraq refused to co-operate with UN weapons inspectors.
According to western officials and military sources, the US and Britain were preparing for a major military campaign against Iraq.
"It is not going to be like Afghanistan and Sudan, firing a few cruise missiles in the air," said a senior western officer familiar with preparations for possible strikes to punish President Saddam Hussein for refusing to co-operate with UN weapons inspection teams. "It is going to be a far-reaching and major operation, provided he does not raise his hands in the air after the first day and say `I've had enough.' "
The point was reinforced by the US defence secretary, Mr William Cohen, who warned that any strike against Iraq would be "significant".
"They will be significant should they be carried out," he said while visiting the US naval base at Norfolk, Virginia. He cut short his trip by an hour to return to Washington for a meeting on the crisis.
Mr Cohen said that no time frame had been decided as to when military strikes might be launched, but stressed that the United States already has a major force in the region in addition to warplanes now being sent.
"I have not seen anything coming out of Baghdad that would indicate he [President Saddam Hussein] is interested in complying with the Security Council resolutions," said Mr Cohen. "We are not seeking to go to war. We are trying to avoid it. The choice is his at this point," Cohen added.
Military experts and officials cited the number of additional US ships, planes and troops being sent to the region as a sign that Washington is planning to bomb Iraq into meeting all UN arms inspection demands. "This does not look like a surgical operation against a few key targets," a western ambassador said.
Washington is sending 18 B-52 and B-1 bombers along with 12 radar-avoiding F-117A stealth jets. The build-up, the second this year, will bring the US force poised near Iraq to more than 300 aircraft and 20 ships, including two aircraft carriers.
Some 3,000 US troops are also expected to go to Kuwait to join the 1,500 regularly deployed near the Iraqi border.
"If you listen closely to Washington and London you will realise that they put stress on the word `decisive' action - that is the critical word. They plan to seriously hit the regime and its capabilities," said a western officer.
But military experts doubt if the operation would include a ground confrontation, as crossing into Iraq could provoke major objections from other world powers and regional states.
"But you never know with Saddam," one Gulf official said. "If he retaliates against the strikes by trying to cross into Kuwait again or fire missiles at neighbours then you could see a need and sufficient support for ground operations."
Although no date has been set, some officials in the region say a strike could be days away, adding that Washington had told Abu Dhabi it would take into consideration the opening of the annual Gulf Arab summit in the United Arab Emirates on December 7th.
The military build-up comes at a time when Gulf Arab states are suffering from a sharp drop in revenues due to weak oil prices.
The US-led military firepower being assembled includes two aircraft carriers, several destroyers and at least one submarine, as well as a considerable variety of aircraft.
An amphibious support group consists of the USS Essex, Duluth and Anchorage, carrying 2,000 marines, five Harriers and four attack helicopters.
The US line-up includes more than 80 combat aircraft on station near Iraq, including A-10 Thunderbolts and F-16 Falcons. Combined with the 75 strike aircraft on the aircraft carrier Dwight D. Eisenhower and the RAF planes, this adds up to a strike force of more than 170 aircraft.
Kuwait is also home to F-117 Stealth bombers. Bahrain is the base for B-1 bombers, and further afield are B-52 bombers on the island of Diego Garcia.
On Wednesday, the US Defence Secretary, Mr William Cohen, ordered a second aircraft carrier, the USS Enterprise, to the Gulf, together with its support ships and a marine force.
British forces include, according to the Press Association, HMS Cumberland, a Type 22 frigate, armed with Harpoon sea-skimming missiles and surface-to-air missiles, with a crew of 250; and HMS Grafton, a Type 23 frigate, which also has Harpoons and Sea Wolf surface-to-air missiles, and has a complement of 174.
The Royal Air Force is making available 12 Tornado GR1 bombers stationed at Ali Al Salem airbase in Kuwait, 35 miles from the Iraqi border; another six of the aircraft are based at Al Kharj in Saudi Arabia. Four Jaguar bombers are stationed at Incirlik in Turkey.