London ? Prime Minister Tony Blair defended Britain’s commitment to stay in Iraq, calling it “crucial for security of the world” but conceded on Sunday he was surprised by the ferocity of the insurgency.

Blair, a firm ally of President Bush in the conflict, said he had not set a deadline for withdrawing some 8,500 British soldiers from Iraq. “There is no arbitrary date being set.”

“But I have absolutely no doubt as to what we should do. We should stick with it,” the prime minister told the British Broadcasting Corp. at the start of the annual Labour Party conference.

Blair conceded he had not expected it to be so difficult to restore order in Iraq following the U.S.-led invasion. “No, I didn’t expect quite the same sort of ferocity,” he said

Although Blair’s party won a historic third term in office, its huge parliamentary lead was slashed, raising questions about Blair’s leadership.