He said "international interference" was partly to blame and called for more time to reach Washington's benchmarks.
In his first public comments since the US released its interim report on Iraq, he said Iraqi forces were ready to take over security if US-led troops left.
President George W Bush also called for his plans to be given more time.
| This report shows that conditions can change, progress can be made, and the fight in Iraq can be won President George W Bush |
In his weekly radio address, Mr Bush said that the last contingent of the 30,000 troops extra troops deployed in Iraq under his so-called surge strategy had only just arrived and needed time to carry out their mission.
"The best way to start bringing these good men and women home is to make sure the surge succeeds," Mr Bush said.
Car bombs
The leaders' comments come amid fresh violence across Iraq.
Police say nine people, all believed to be Shia men from the same extended family, were shot dead in a village near Hilla, south of Baghdad, after gunmen raided a house.
The US military reported that it had killed six suspected insurgents in an air strike near Baquba, north of Baghdad.
A translator working for the Reuters news agency has also been killed - the third Reuters employee to die this week.
And police also announced that 21 unidentified bodies had been found on the streets of the capital on Friday.
Despite the ongoing unrest, Mr Maliki said he had "full confidence" Iraqis could take responsibility for security, even if "international forces withdraw at any time they want".
However, he did say Iraqi forces needed additional training and equipment to be ready in case of a withdrawal.
'Facing the challenges'
Reacting to the White House's report on political progress in Iraq, which was presented to Congress on Thursday, Mr Maliki said that the Iraqi government needed "time and effort" to bring about the necessary reform.
He said the political process was "facing security, economic and services pressures, as well as regional and international interference".
Rebuffing negative reaction to the report, Mr Maliki said that in fact "these difficulties can be read as a big success, not negative points, when they are viewed under the shadow of the big challenges".
"This report shows that conditions can change, progress can be made, and the fight in Iraq can be won," he said.
The shows of confidence from the US and Iraqi presidents comes at a time of increasing pressure from Congress and the public for the White House to change its strategy in Iraq.
Two leading politicians from Mr Bush's own party on Friday called on him to draw up plans for a possible withdrawal of American forces from Iraq.
The two Republican senators - Richard Lugar and John Warner - said they wanted to ensure that US military and diplomatic policy was prepared for change.
They also suggested American forces in Iraq should concentrate on tracking down insurgents and securing its borders, rather than trying to prevent sectarian violence.
On Thursday, the US House of Representatives voted in favour of pulling US combat troops out of Iraq by April next year.