"There is a need for co-operation between Islam and Christianity to help solve the continuing problems ... fighting terrorism comprehensively and deeply requires the involvement of all nations, religions and civilizations," the state-run radio quoted Khatami as telling the Pope in a phone conversation.
Khatami added that Iran was "concerned over possibility of innocent people falling victim" in the fight against terrorism, the radio said.
The United States is mobilizing forces for strikes against terrorist bases in Afghanistan, which hosts Osama bin Laden, the prime suspect in the Sept. 11 attacks on New York and Washington.
Khatami also said Iran wanted to work with the Vatican in drawing up a "correct and comprehensive definition of terrorism." Khatami has expressed deep regret and sympathy over the Sept. 11 attacks, but has called for a campaign against terrorism to be orchestrated by the United Nations rather than the United States.