The comments by Mouwaffak al-Rubaie were the strongest yet by an Iraqi official about the deal now under negotiation with U.S. officials. It came a day after Iraq's prime minister first said publicly that he expects the pending troop deal with the United States to have some type of timetable for withdrawal.
U.S. President George W. Bush has said he opposes a timetable. The White House said Monday it did not believe al-Maliki was proposing a rigid timeline for U.S. troop withdrawals.
U.S. officials had no immediate comment Tuesday on al-Rubaie's words.
Al-Rubaie spoke to reporters after briefing Grand Ayatollah Ali al-Sistani in Najaf on the progress of the government's security efforts, and the talks.
"Our stance in the negotiations underway with the American side will be strong ... We will not accept any memorandum of understanding that doesn't have specific dates to withdraw foreign forces from Iraq," al-Rubaie sid.
Some type of agreement between the United States and Iraq is needed to keep U.S. troops in Iraq after a U.N. mandate expires at year's end.
U.S. officials have said little publicly about the negotiations. Adm. Michael Mullen, chairman of the Joint Chiefs of Staff, did not comment directly on the specifics when asked about it on a trip to Baghdad.
"We'd all like to see U.S. troops get out of here at some point in time," Mullen said. "However, from a military perspective I need the laws and the regulations and the agreements from the government of Iraq in order to continue operations beyond the 31st of December of this year."
On Monday, Mullen , saying, "From all I see, the security conditions are holding, the level of violence is down; we're down to a level that we haven't seen in over four years."
Iraq's government has felt increasingly confident in recent weeks about its authority and the country's improved stability, and Iraqi officials have sharpened their public stance in the negotiations considerably in just the last few days.
Violence in Iraq has fallen to its lowest level in four years. The change has been driven by the 2007 buildup of American forces, the Sunni tribal revolt against al Qaeda in Iraq and crackdowns against Shiite militias and Sunni extremists.
In other developments: