At least 11 inmates escaped from a Greek prison after gunmen brazenly attacked the site with grenades and automatic weapons, kicking off a nightlong standoff between police and prisoners. Two guards were injured, one of them seriously, The Associated Press reported.

A police official, speaking on condition of anonymity because he was not authorized to talk to the media, told the AP that two of the escaped inmates had been found and arrested. He said they were hiding in a church not far from the site of the prison. The official added that all the escapees were Albanian.

The incident occurred near the town of Trikala, in central Greece, some 320 kilometers northwest of Athens. As many as six gunmen attacked the prison after driving up to the site in a van and pickup truck, according to officials.

The Ministry of Justice announced that gunmen using "two vehicles and very heavy weapons" attacked the prison's outside guards, as well as a prison patrol vehicle and two police cars.

"During the exchange of heavy fire that lasted over half an hour and turned the area into a battlefield, two perimeter guards were injured in the abdomen, one of them seriously," the ministry said.

Prison authorities were investigating reports that weapons had also been fired from inside the facility. The ministry's announcement said that "no guns or casings confirming the use of an automatic weapon by inmates during the escape have been found. However, the search continues."

At least five grenades exploded, while army experts were expected at the prison to dispose of two unexploded grenades.

The attack started at around 8:30 pm (1830GMT) Friday, when a police patrol jeep was fired upon.

A bullet fired at the village damaged a coffee shop window in an incident also being investigated by police.

The escaped prisoners used ropes and bed sheets tied together to climb down from a guard tower that had been attacked. They had to go through two more perimeter fences, topped by barbed wire, before they escaped. The same police officer told the Associated Press that wire-cutting tools had been recovered.

Police set up roadblocks near the prison and searched vacant homes and farm buildings, as well as using two helicopters, in the manhunt. Officers from evidence units were also scouring the jail perimeter after dawn.

The attack was the latest dramatic incident at Greek prisons, which are suffering from serious overcrowding and staff shortages as the country struggles through financial crisis and a recession that started in late 2008.