Militants stormed an office of Iraq's human rights ministry in northeast Baghdad on Thursday and took a number of civil servants hostage, security officials said.
The attack was mounted by eight armed men, said police and an interior ministry official.
Security forces sealed off the surrounding area, where several government buildings are located including the main headquarters of the transport ministry.
It was not immediately clear if any casualties had resulted from the militant attack.
A spokesman for the human rights ministry did not immediately respond to requests for comment.
No group claimed responsibility for the assault, but Sunni militants affiliated with the Al-Qaeda-linked Islamic State of Iraq and the Levant, or ISIL, have in the past mounted similar armed attacks on Iraqi government buildings.