KIRKUK, Iraq — Two weeks after fighting together against the Islamic State, Iraqi forces pushed their Kurdish allies out of the disputed city of Kirkuk on Monday, seizing oil fields and other facilities amid soaring tensions over last month’s Kurdish vote for independence.

The move by the Iraqi military and its allied militias so soon after neutralizing the Islamic State in northern Iraq hinted at a country that could once again turn on itself after disposing of a common enemy.

Civilians and federal troops pulled down Kurdish flags around the city. Kurdish Gov. Najmaddin Karim, who had stayed at his post despite being dismissed by Baghdad weeks ago, fled to Irbil, the capital of Iraq’s autonomous Kurdish zone.