Bomb outside Turkish AK Party building wounds 6

ISTANBUL (Reuters) - A bomb exploded outside a local headquarters building of Turkey's ruling AK Party in Istanbul on Monday, wounding six people, including four police officers, a local official said.

Istanbul Governor Muammer Guler said two officers were in critical condition after the blast went off in Sutluce district, on the European side of the city. Two AK Party staff workers were among the wounded, Guler said.

Investigators believed the bomb was hidden in a package, Guler told reporters.

The blast broke windows at the entrance of the building, but appeared to have caused little structural damage.

There was no immediate claim of responsibility.

Kurdish separatists, far-left groups and Islamists have carried out bombings in Istanbul in the past.

In an unrelated explosion caused by a gas leak, three people were killed and 17 injured in an explosion in a municipality building in the province of Kocaeli, neighbouring Istanbul, a local official said.

(Editing by Charles Dick)