There were scenes of panic at the Council of State - the top administrative court - as the injured were carried out of the building.

The attacker, believed to be a lawyer, was detained by police and is being questioned but his motive is not clear.

One of the wounded judges had been criticised for ruling against teachers wearing Muslim headscarves.

Judge Mustafa Birden made headlines earlier this year when he ruled that schoolteachers, who are banned from wearing the Islamic headscarf at work, could not cover their heads even on their way to school. He has reportedly received death threats since then.

The judge was shot in the stomach and has undergone surgery. Doctors said his injuries were not life threatening.

However Judge Mustafa Yucel Ozbilgin was shot in the head and was in a critical condition, doctors said.

The attacker was apparently carrying papers that identified him as a lawyer - though it is not known if these were genuine - and made it past security guards undetected.

He reportedly shouted "Allahu akbar" (God is great) as he fired his weapon.

Tansel Colasan, deputy head of the Council of State, said the attacker yelled "I am the soldier of God", and said he was carrying out the attack to protest against the court's decision on headscarves.

He was arrested immediately.

The judges were part of the court's second chamber, which deals with education issues.

Political row

The BBC's Sarah Rainsford in Istanbul says the attack has helped fuel widespread speculation that the court was targeted for its strict, some say hardline, adherence to secular principles.

The court's decision on headscarves has been condemned as illegal by Prime Minister Recep Tayyip Erdogan, whose ruling party has Islamist roots.

Mr Erdogan, though, was quick to condemn Wednesday's attack, and said the culprit would be severely punished.

Nevertheless Deniz Baykal, chairman of the secularist main opposition Republican People's Party, said the government's policies were responsible.

"I hope those who still can't see where Turkey is being dragged, who refuse to see it, will take this as a warning," he said.

"Unfortunately, blood has spilled into politics in Turkey. Turkey is being dragged into a very dangerous situation. Everybody should come to their senses."

President Ahmet Necdet Sezer said the attack would not undermine Turkey's secular constitution.

"These attacks will never reach their goal," he said, adding that the justice system would not be intimidated and would be loyal "to the secular and democratic republic".