The United States taxpayer is paying a heavy price for the military buildup in the Persian Gulf - which is set to continue indefinitely while the world watches whether Iraq will keep its word on weapons inspections. The Pentagon's presence in the area since November had cost 'well over US$600 million (HK$4.6 billion)' so far, and the price tag was likely to keep rising steadily, Deputy Defence Secretary John Hamre said. With thousands of soldiers and more hardware continuing to arrive in Kuwait, questions are beginning to be raised in Washington about the inevitable costs. The issue was put in focus on a day the UN-brokered peace deal came under attack on Capitol Hill, with Senate leader Trent Lott saying it represented a cave-in to Iraqi leader Saddam Hussein. CBS News also reported on Wednesday that US intelligence agents were investigating an apparent attempt by Iraq to convert an L-29 jet trainer into an unmanned aircraft to carry tanks filled with nerve gas or anthrax. Britain and the US have drafted a Security Council resolution warning Iraq of the 'severest consequences' if it violates the accord. The draft does not spell out the use of force, which Russia, France and China oppose. The US now has the biggest presence in the Gulf since the 1991 Gulf War. In addition to more than 25 warships, headed by two aircraft carriers, there are at least 35,000 troops and 400 combat aircraft, including F-16s, B-1 bombers and F-117 Stealth fighters. The cost of mounting the operation is having the knock-on effect of leaving the US presence considerably weakened in other danger spots. The Pacific forces have been left without an aircraft carrier, and US commanders in the region have expressed concern South Korea has become more vulnerable to attack from the North. They have requested extra air force squadrons and gunships. The buildup in the Gulf seems to be testing the Pentagon's stated objective of always being prepared to enter into combat in two separate zones at one time. The planned attack on Iraq had promised to be a high-profile testing ground for a new array of 'smart weapons', including satellite and laser-guided missiles. Mr Hamre said the Pentagon would soon go to Congress for more funds. Weapons inspectors could ensure Iraq was cleared of weapons of mass destruction much more quickly under the new access accord than previously, chief UN inspector Richard Butler said.