Saddam Hussein's development of weapons of mass destruction pose a "very great considerable threat" to international security, says the British Foreign Secretary Jack Straw.
Diplomatic pressure on the Iraqi leader to re-admit international weapons inspectors must be an "intensified", the British Foreign Secretary told MPs.
The British Foreign Secretary also said Britain wants to commit forces to the international stabilisation force agreed by Afghan leaders in Bonn.
But asked whether military action could be taken against Iraq, Mr Straw told the Commons Foreign Affairs Select Committee: "I am not going to speculate on that."
"Hawks" inside President George Bush's administration are said to see Iraq as the logical next target for US troops.
Britain has said any military action could only be justified if evidence of Iraqi involvement in the September 11 atrocities was produced. Mr Straw told the committee that was a separate matter to international concern over Iraq's weapons programme.
But international law allowed any country receiving "very good information" that another country or terror organisation was planning an attack to take pre-emptive military action as a form of self-defence, he said.
Mr Straw went on: "We are concerned, very concerned, about Iraq's development of these weapons and we believe action must be taken."
He praised Afghan leaders meeting in Bonn for agreeing on an interim government to take control following the Taliban's collapse. The Foreign Secretary said that "happily" the agreement included provisions for a stabilisation force, and Britain would want to contribute to that.
"There is work going on that because our forces are literally the best in the world ... people tend to put the United Kingdom at or near the top of any list," he told MPs.
It would be up to British Defence Secretary Geoff Hoon to say what any British contribution might be, Mr Straw said.
"But we would like to do that," he added.