Iraq's air force, slowly taking shape after years of war, is too weak to take control of the skies and defend the country until at least 2020, the air force chief said in an interview.

The United States formally ended combat operations in Iraq in August but still maintains 50,000 troops in the country to help its fledgling army tackle Islamist insurgents.

Iraq still depends on US forces to scramble combat aircraft to aid its ground forces, and US officials have admitted the country is not yet ready to defend its borders on its own.

In strikingly frank remarks, Staff Lieutenant General Anwar Ahmed told Reuters the fighting strength of his force was too low to take over aerial control any time soon.

"As for the Iraqi air force in its current state, it is not prepared to deter any foreign attack," he said late on Tuesday in his home inside Baghdad's heavily fortified Green Zone.

"In the modern military sense, the Iraqi air force cannot be completed before 2020, and until then we would not be able to say that the air force is ready to defend the skies."

Originally founded in the 1930s when Iraq was under British rule, the Iraqi air force is still a shadow of its former self.

Under dictator Saddam Hussein, who was ousted in the 2003 U.S. invasion, it grew into one of the region's biggest forces, consisting of hundreds of mainly Soviet-designed planes. After the invasion, Washington disbanded Iraqi forces altogether.

Funded out of the Iraqi state budget, which relies on oil exports for most of its revenues, and assisted by the US military, the air force is now taking steps to rebuild itself, but the process is painfully slow.

"Building an air force is a tough job," Ahmed said.  "You can create an infantry regiment in a record time, but the air force cannot be built in a short period of time."

He refused to say how many aircraft Iraq now operated, nor would he reveal the number of Iraqi pilots. There are no public figures on the size of the air force, and defence ministry officials have declined to comment on the matter.

In a further setback, the defence ministry's 2008-2020 air force revival plan was hit by a drop in oil prices as well as the global financial crisis, Ahmed said, without elaborating.

He said the key problem was the lack of combat jets, while adding Iraq had "enough" reconnaissance and training planes.

US forces officially remain in Iraq to "advise, train and assist" until their full withdrawal in late 2011, but Iraqi forces still rely on its fighter jets to provide backup.

In September, US troops brought in attack helicopters and F-16 jets when Iraqi soldiers asked for help during a gunfight with militants in Diyala province.

For foreign companies, Iraq's ambitions offer a chance to tap a new market. France, Russia and China have all been jockeying to help fill Iraq's huge arms wish list, which includes multi-role fighters to defend its air space.

The top US commander in Iraq said in June he expected the United States to meet a long-standing Iraqi request for new Lockheed Martin Corp F-16s - a powerful symbol of US co-operation with Iraq.-Reuters