Iraq's National Security Advisor Muwafaq al-Rubaie said Tuesday that his country will reject any security pact with the United States unless a specific date for withdrawal of U.S.-led troops is set, according to reports from the holy city of Najaf.

"Our stance in the negotiations with the Americans will be strong. We will not sign any memorandum of understanding without specifying a date for the withdrawal of foreign troops from Iraq," Rubaie told reporters in Najaf.

Rubaie's comments came after his meeting with Shiite cleric Grand Ayatollah Ali al-Sistani, during which Rubaie briefed him on the progress of his government's security efforts and the ongoing talks over the security agreement with the United States. Rubaie's new strong remarks also came a day after Iraq's Prime Minister Nuri al-Maliki said that his country was seeking a timetable for the withdrawal of U.S. troops as part of its negotiations with the United States on the status of U.S. forces in Iraq beyond 2008.

"The current trend is to reach either a memorandum of understanding for the departure of the troops, or a memorandum of understanding for setting a timetable for its withdrawal," Maliki said during a meeting with a group of Arab ambassadors in Abu Dhabi, capital of the United Arab Emirates, a day before ending his visit to the Gulf country.

However, the United States immediately rebuffed Maliki's comments, saying that its talks with Iraq on future U.S.-Iraq relations will not include a date for the U.S. troops to withdraw from the Middle East country.

"It is important to understand that these are not talks on a hard date for a withdrawal," White House spokesman Scot Stanzel said.

"As (U.S.) Ambassador (Ryan) Crocker has said, we are looking at conditions, and not calendars -- and both sides are in agreement on this point," Stanzel added.