President Bush bluntly warned Iran yesterday that it would face the consequences if it harboured any al-Qa'ida fighters fleeing from Afghanistan.
Mr Bush demanded that Iran give evidence that it has sided with the United States in its war against terrorism.
"Iran must be a contributor in the war against terror," he told reporters. "Our nation and our fight against terror will uphold the doctrine: either you're with us or against us.
"And any nation that thwarts our ability to rout terror out where it exists will be held to account, one way or the other."
After the US victory against the Taliban in Afghanistan, debate has centered on which country should be the next focus of its war against terrorism. Some hawks have urged action against Iraq, and aerial surveillance along the coast of Somalia has been stepped up.
But Mr Bush has turned the spotlight on Iran, amid fears that the Islamic state has been flexing some muscles around its border to head off Western influence in Afghanistan – although he said that the US would deal in "diplomatic ways, initially" with any attempt to undermine Afghanistan's interim government.
Iran swiftly denied, however, that it had protected al-Qa'ida members. A foreign ministry spokesman, Hamid Reza Asefi, said: "Our borders are tightly closed and the Islamic Republic of Iran in no circumstances would let al-Qa'ida members, fighters and supporters of bin Laden enter the country."
An Iranian Vice-president, Mohammad-Ali Abtahi, said: "Iran has never been on good terms with the Taliban and their supporters. It has been our policy not to allow terrorist groups such as al-Qa'ida in Iran."
Many analysts believe that Iran, which hated the Taliban, is merely doing what Russia and Pakistan are doing: working with local warlords to guarantee their interests in Afghanistan do not get swept aside.Reuse content