British Prime Minister David Cameron said that Sunni Islamist insurgents fighting in Iraq were planning to attack Britain EVand that ''ungoverned spaces'' where militants thrived had to be shut down.
Cameron spoke out as Iran's president vowed to defend Shi'ite holy sites in Iraq, where Sunni militants battled their way into the biggest oil refinery in what is rapidly turning into a sectarian war across the frontiers of the Middle East.
Britain has ruled out any military involvement in Iraq, but has sent an ''operational liaison and reconnaissance team'' to Baghdad and is providing humanitarian aid.
It has also pledged to crack down on Britons travelling to the region to fight alongside the insurgents.
But Cameron, who is chairing a meeting of Britain's National Security Council to discuss the subject later on Wednesday, said his country could not afford to stand on the sidelines.
''I ... disagree with those people who think this is nothing to do with us and if they want to have some sort of extreme Islamist regime in the middle of Iraq it won't affect us. It will,'' Cameron told parliament.
''The people in that regime as well as trying to take territory are also planning to attack us here at home in the United Kingdom.''
The head of Iraq's state-run South Oil Company Dhiya Jaffar said that Exxon Mobil has carried out a ''major evacuation'' of their staff and BP had evacuated 20 percent of its staff.
He said ENI, Schlumberger, Weatherford, and Baker Hughes had no plans to evacuate staff from Iraq following the lightning advance of Sunni militants through the country.
The companies, which are based in southern Iraq where the government is still in firm control, were not immediately available for comment.
''This message is not satisfactory for us. We are not convinced the work should not be done remotely. They should be here on the ground,'' Jaffar said.
''I assure the companies that the current developments in the country have not affected and will not affect in anyway the operations in the south,'' he said, adding that the export level for June will be 2.7 million barrels per day.