Iran's foreign minister has strongly denied reports his country was allowing al Qaeda members to cross the border from Afghanistan.
President George W Bush warned Iran on Thursday against harboring members of the al Qaeda network who fled Afghanistan or seeking to destabilise the fledgling central authority.
"In fact we have totally closed our borders and we are taking care of any passing of the border by any elements from Afghanistan," foreign minister Mr Kamal Kharrazi told reporters after discussions with UN Secretary-General Kofi Annan.
"More than that, we have established visas between Iran and Arab countries in our region to avoid any sort of unwanted guests," he said.
"If there are any members (of al Qaeda) found on Iranian soil they certainly would be apprehended by Iranian authorities," he added.
During his talks with Mr Annan, Mr Kharrazi initiated a discussion on the reports and denied the allegations in detail, particularly charges concerning the new Kabul authorities that the United Nations backs, sources close to the secretary-general said.
On warlords ignoring the new Kabul authority, Mr Kharrazi said "Iran did have relations with some provincial leaders but we encourage them to cooperate with the central government because we believe security will be maintained if the supreme authority is successful."