Northern Iraq grows violent. Hundreds of Iraqi police in Baghdad poisoned

KIRKUK, Iraq - Bombings and shootings are increasing in Iraq's north as part of a power struggle between Arabs and Kurds. Car bombings in oil-rich Kirkuk grew fivefold last month and hundreds of Kurdish families have left the north's biggest city, Mosul, to escape the violence.

The bloodshed is not nearly on the scale of Baghdad, where thousands have died in recent months in a wave of sectarian killings and insurgent attacks. In the provinces where Mosul and Kirkuk are located, the toll has been several hundred during the summer.

But the creeping violence in the north — a region U.S. officials had hoped was getting more stable — underlines the difficulty in keeping all of Iraq's potential hotspots under control at once.

It also suggests growing strains in another of Iraq's sectarian divides. Baghdad has been suffering from violence between Sunni and Shiite death squads. In the north, the tensions are between Arabs and Kurds, who claim Kirkuk as part of their autonomous zone of Kurdistan to the north.