Baghdad- A group of al Qaeda prisoners was caught trying to tunnel out of Iraq's Abu Ghraib prison, an official said on Sunday, after the militants said they would  step up their fight against the government.

Iraq's Shi'ite-led government is concerned that Sunni Muslim militants will get a boost from the insurgency in neighboring Syria, where mainly Sunni rebels are battling President Bashar al-Assad.

Jail breaks are common in Iraq and security at prisons was beefed up this week after five militants stormed a police counter-terrorism headquarters on Tuesday in an attempt to free al Qaeda prisoners. All five were killed in a long gun battle.

A spokesman for the justice ministry, Haider al-Saadi, said in a statement that 11 "dangerous prisoners" at Abu Ghraib dug down three meters and had tunneled along 20 meters using a frying pan and part of a ceiling fan before they were discovered.

They had fashioned breathing apparatus from soft-drink cans stuck end to end.

Another official in the ministry told Reuters that the men were al Qaeda members. The high security prison, notorious for abuse both during the rule of Saddam Hussein and under U.S. occupation, houses several thousand convicted militants.