Twenty-three suspected insurgents escaped Friday from a detention center in the city of Mosul in northern Iraq by digging a hole in the wall and climbing through, officials said.
Guards discovered the escape from al-Ghazlani Detention Center when they entered the men's cell to distribute lunch at noon, the officials said.
The men, who were being held pending trial, had been in the cell at 6 a.m., when breakfast was served, the officials said.
A number of the center's security forces have been detained in connection with the investigation and pictures of the escapees have been distributed to security checkpoints in Nineveh province, officials said.
The escape had apparently been planned for some time: guards had seen a blanket covering the hole in the brick wall, which would have taken more than a day to breach, the officials said.
Mosul is located in Nineveh province, about 420 km (260 miles) north of Baghdad.
- CNN's Mohammed Tawfeeq contributed to this story.