Iraq's top army officer has criticised as premature the planned US troop withdrawal by the end of next year.
Lt Gen Babaker Zebari warned that the Iraqi military might not be ready to take control for another decade.
The US says it is on target to end combat operations by the end of August and meet its deadline for removing all troops by the end of 2011.
It has 64,000 soldiers in Iraq. About 50,000 will remain until 2011 to train Iraqi forces and protect US interests.
Gen Zebari's warning echoes the remark by Saddam Hussein's former Foreign Minister Tarik Aziz last week that the Americans were "leaving Iraq to the wolves".
But the White House says President Barack Obama is satisfied with the progress made in Iraq, which will allow US troops to transfer security to local forces as planned.
Gen Zebari told a defence conference in Baghdad that the Iraqi army would not be able to ensure the country's security until 2020 and that the US should keep its troops in Iraq until then.
"At this point, the withdrawal [of US forces] is going well, because they are still here, but the problem will start after 2011," he said.
"The politicians must find other ways to fill the void after 2011... If I were asked about the withdrawal, I would say to politicians: the US army must stay until the Iraqi army is fully ready in 2020."
Violence in Iraq has fallen since the peak of sectarian warfare in 2006-2007, but the number of civilian deaths from daily bombings, shootings and other attacks rose sharply in July.
The general's remarks contradict government policy - which is to stick to the State of Forces Agreement (Sofa) which set the timetable for the US withdrawal, says the BBC's Hugh Sykes in Baghdad.
There is a lot of anxiety in Iraq that the Americans are rushing away because the Democrats are afraid of losing votes in mid-term elections in November, our correspondent adds.
In Washington on Wednesday, White House spokesman Robert Gibbs attributed the recent rise in attacks to the Islamic fasting month of Ramadan, which has previously coincided with a spike in insurgent activity.
"We continue to anticipate... a traditional up-tick of violence around Ramadan and as those [insurgents] that are left try to gain attention," he said.
Mr Gibbs gave a positive assessment of the situation in Iraq, based on a briefing by Gen Ray Odierno, the US commander there, to President Obama.
Gen Odierno "reported that the security situation has retained the significant improvements made over the last couple of years and that Iraqi security forces are fully prepared to be in the lead when we end our combat mission later this month."
More than 100 people have died in attacks across the country so far this month. July was Iraq's deadliest month since 2008.
Iraq is also grappling with a five-month-long political impasse after a March parliamentary poll failed to produce a clear winner.
Despite the challenges, Congressman Adam Smith, a Democratic member of the US Armed Services Committee, said the US was right to pull out.
"Iraq is not going to be a 100% stable place for quite a while, but a US foreign military presence is not going to force stability upon the Iraqi people. They are going to have to stand up and claim it for themselves," he told the BBC's Today programme.
He said there would always be risks, regardless of when US troops pulled out of Iraq.
But Faleh Abdul-Jabbar, the director of the Baghdad-based Iraq Institute for Strategic Studies, told the BBC the US withdrawal would be "counter-productive for so many reasons," pointing to Iraq's political vacuum and its "weak army and reviving insurgency".
"Withdrawal at this point would send the wrong signals to the political class, saying that the US is withdrawing no matter what. And second, it would send the wrong signal also to the insurgency - dormant or active - that we are withdrawing no matter what, and they would see it as a retreat," he added.