United Nations weapons inspectors in Iraq have set up a permanent base in the northern city of Mosul, in a drive to speed up the search for evidence of weapons of mass destruction.

In a further escalation of tension aircraft taking part in US-British patrols attacked military communication sites in the south of Iraq.

The US military said Saturday's strike, on targets south-east of Baghdad, was "in response to Iraqi hostile acts".

But an Iraqi military spokesman insisted the planes had hit civilian targets.

The US is preparing to boost its troop numbers in the Gulf region, with the addition of about 17,500 Marines and 11,000 infantry.

Britain is also reported to be planning to send thousands of troops to the region.

Iraq's foreign minister has accused the US of violating international law by backing mercenaries against President Saddam Hussein.

In a letter to the United Nations, Naji Sabri said such actions were "part of US acts of aggression and terrorism committed against Iraq since 1990," Iraqi state media reported.

Accelerating checks

A UN inspection team left for Mosul, 375 kilometres (220 miles) north of Baghdad, on Saturday.

US MILITARY BUILD-UP

60,000 troops currently stationed in Gulf About 28,500 extra troops to be deployed in coming weeks Aircraft carrier USS Constellation is in the Gulf, while USS Harry S Truman is in the Mediterranean Biggest regional build-up since the 1991 Gulf War

The base to be set up there "will help us expand and accelerate our inspections throughout the country, but particularly in the north," UN spokesman Hiro Ueki told reporters.

The inspectors also paid their first visit to Iraq's second city, the southern port of Basra, on Saturday.

Other inspectors went to a brewery at Khalis, about 50km (30 miles) north of Baghdad, and the Al Maamoun plant at Mamoudiyah, just outside the capital.

The Iraqi authorities said earlier this week that the UN had inspected 230 sites, but had found nothing incriminating.

US military might is building up in the Gulf

The teams resumed work on 27 November, in line with a new resolution unanimously adopted by the UN Security Council ordering Iraq to reveal all details of its weapons programmes or "face serious consequences".

The chief weapons inspector, Hans Blix - who is to visit Iraq again himself in two weeks' time - is due to make a progress report to the UN on 27 January.

He has said that the findings will include the results of laboratory tests of samples taken in Iraq.

US President George W Bush rallied US troops on Friday, telling them that a war in Iraq would be "not to conquer but to liberate".

He urged Iraqi leader Saddam Hussein to "end his defiance" of UN resolutions and avoid US-led military action.