US Secretary of State Condoleezza Rice has spoken to Iraqi leaders to help advance negotiations for a deal on the future presence of US troops in Iraq, her spokesman said Thursday.

But State Department spokesman Sean McCormack said the two sides have still not clinched a Status of Forces Agreement (SOFA) to set out the role and duties of US troops after a UN Security mandate expires December 31.

"I have nothing new to report. The process continues," McCormack told reporters during the daily press briefing. "The Iraqis are … considering the text (of an agreement). We are talking to the Iraqis."

McCormack said Rice spoke by telephone on Wednesday with Prime Minister Nuri al-Maliki as well as with President Jalal Talabani and Vice President Adil Abd al-Mahdi about boosting the SOFA negotiations.

"She did speak with some of the Iraqi leaders yesterday (Wednesday)," McCormack said.

"Her focus is on moving this SOFA process forward," McCormack said when asked if Rice and her Iraqi interlocutors spoke about other options if the two sides fail to reach agreement by the end of the year.

Both US and Iraqi leaders have stressed that a deal is in the works.

But they have differed over some issues such as granting immunity to US soldiers for acts committed in Iraq, whether Washington has the right to detain Iraqi prisoners and on the future command of military operations on the ground.

The deal was originally set to be signed in July, but has been held up by the ongoing negotiations.