Ambassador Crocker said U.S. officials responded by saying coalition forces are in Iraq by invitation of the Iraqi government and under U.N. Security Council authority and the United States has spent billions of dollars training Iraqi security forces.

The ambassador also said Iran had proposed setting up a "trilateral security mechanism" among Iraq, Iran and the United States. He did not provide details on the proposal and said it would be studied by officials in Washington.

In Tehran on Monday, Iran's foreign minister said the best way to end the sectarian fighting in Iraq would be an immediate pullout of U.S. forces.

The talks in Baghdad were a rare meeting between high-ranking Iranian and American officials. The United States broke off diplomatic ties in 1979 following the seizure of the U.S. embassy in Tehran. Ambassador Crocker described Monday's meeting as "businesslike" and focused exclusively on the security situation in Iraq. He said Iranian officials did not raise the issue of five detained Iranians held in U.S. custody.

The ambassador said the Iraqi government proposed another similar meeting among representatives of the three countries. He said U.S. officials would consider the invitation after they receive it.