The future of the 150,000 US troops remains uncertain as US and Iraqi officials struggle to reach a common agreement, which would dictate the American military presence after a UN mandate expires at the end of the year.
Both countries are under pressure to conclude the agreement, which would allow US troops to stay in Iraq until 2011.
The Iraqi officials' comments came as a roadside bomb killed one policeman and wounded three others when it hit their patrol in Kamaliya district, eastern Baghdad, police said.
After months of negotiations, the security deal appeared close to complete until Iraqi officials requested amendments including greater Iraqi legal jurisdiction over US troops and guarantees that US troops would not launch attacks into other countries.
The last point took on greater importance for Iraq following a US raid last week into Syria close to the Iraqi border.
Some of Iraq's neighbours, such as Iran, oppose the security pact, a fact that has made embracing the pact a difficult proposition for Iraqi politicians close to Tehran.
After the content of a deal is finalised by both Washington and Baghdad, it must also be backed by the Iraqi parliament.
In a related development, a senior Iraqi Kurdish leader has said the US military could have bases in northern Iraq if Washington and Baghdad failed to sign the security deal, according to a local newspaper.
Massoud Barzani, the president of northern Iraq's regional Kurdish administration, said that his government would "welcome" such a move, the Khabat, a newspaper run by Barzani's Kurdistan Democratic Party, quoted him as saying on Sunday.
"All the attempts are going right now to sign the pact, but if the pact is not signed and if US asked to keep their troops in Kurdistan, I think the parliament, the people and government of Kurdistan will welcome this warmly."