LONDON, April 1, 2008 (AFP) - Britain is to delay a planned reduction of forces in southern Iraq, following recent unrest around Basra, Defence Secretary Des Browne said Tuesday.

The move will likely be welcomed by the United States, which is reportedly counting on British forces to help maintain order in southern Iraq while the 'surge' centred on Baghdad continues.

The British government announced last October that it hoped to reduce troop levels to 2,500 in the spring, but that has been called into question by recent events, said Browne.

'It is prudent that we pause any further reductions,' he told the House of Commons, saying there were currently around 4,000 British soldiers in southern Iraq.

'It is absolutely right that military commanders review plans when the conditions on the ground change,' he added.

'At this stage we intend to keep our forces at the current levels of around 4,000, as we work with our coalition partners and with the Iraqis to assess our future requirements.'

Under former prime minister Tony Blair, Britain controversially joined the US-led invasion of Iraq in 2003, but his successor Gordon Brown has made clear his strategy of cutting troop numbers since taking office last June.

The move has led to reported strains between London and the administration of US President George W. Bush, which last year launched a 'surge' strategy aimed at reducing violence still gripping the country five years after the war.

The 4,000 British troops are mostly stationed at Basra airport where they withdrew to after leaving their Basra Palace base in the centre of the southern port city in early September.

British forces handed Basra province over to Iraqi control mid-December and have since been involved mainly in training Iraqi troops and conducting joint patrols.

US and British forces have said they have been giving air support to operations since Tuesday by Iraqi forces against Shiite militiamen in areas of Basra controlled by the Mahdi Army militia of radical cleric Moqtada al-Sadr.

Browne confirmed that British forces had been supporting the Iraqi forces in a range of ways, including sending jets to overfly Basra city as a show of force, as well as using helicopters to help re-supply the Iraqis.

Last month a British newspaper reported that the United States plans to urge Britain to launch a 'surge' in Basra to combat increasing violence in the region.

An unnamed senior US military source was quoted by the Sunday Mirror as saying: 'The plan is to turn the coalition's attention on to Basra and we will be urging the British to surge into the city.

'If (Iraqi forces) do not have enough troops, then they will be offered US Marines to help out.

'The feeling is that if southern Iraq is hugely unstable, it will affect the success of the surge in the north and destabilise the whole country.'

Iraqi Prime Minister Nuri al-Maliki said in Baghdad Tuesday that the recent crackdown on Shiite militiamen in Basra was a 'success' and that 10,000 extra troops would be recruited to keep order in the southern city.

Browne said he hoped to give an update on Britain's troop plans for Iraq later in April.