Manouchehr Mottaki told a ministerial meeting of Iraq's neighbors and key international players, including U.S. Secretary of State Condoleezza Rice, that the U.S. should present a clear plan to withdraw its forces "in order to allow the return of peace and stability."
He also called for the immediate release of five Iranians detained in northern Iraq by U.S. troops in January, calling their abduction a "brazen contravention of international conventions."
"We hold the perpetrators of this clumsy adventurous act responsible for its consequences," Mottaki said, without naming the United States.
The detention of the five has emerged as a major sore point between the U.S. and Iran, who are deeply divided over Iraq as well as Tehran's controversial nuclear program. Mottaki had at one point suggested he might not attend the two-day conference in the Egyptian resort of Sharm el-Sheik unless the five were freed. The United States accuses the five of helping finance and arm militants in Iraq, a claim Iran denies.
Mottaki's speech angered the Iraqi delegation, led by Prime Minister Nouri al-Maliki, who has sought to bridge the disputes between Tehran and Washington and - more broadly - rally all the deeply divided nations of the region behind a plan to stabilize Iraq.
His comments were just "to settle accounts," said one al-Maliki aide, speaking on condition of anonymity because of the sensitivity of the issue. "We didn't expect it to be in this manner."
Mottaki told the delegates that "the continuation of and increase in terrorist acts in Iraq originates from the flawed approaches adopted by the foreign troops. Thus, in our view, the continuation of occupation lies at the origin of the crisis."
"The United States must accept the responsibilities arising from the occupation of Iraq, and should not finger point or put the blame on others," he said.
Iraq had hoped that Rice and Mottaki would meet during the conference, which was ending Friday. But the only contact between the two was a wary exchange of pleasantries over lunch on Thursday.