Rice will press prime minister Nouri Maliki and other top Iraqi officials to iron out remaining differences in a US-Iraq security deal that is intended to lead to the withdrawal of American troops.

She said negotiators had made significant progress but an agreement was not imminent.

She flew into Baghdad amid indications that a draft deal had been concluded, but she said that was premature.

US officials said more work was needed to reach agreements on a timeline for withdrawals, immunity for US troops and the handling of Iraqi prisoners.