MOSUL, Iraq,  (Reuters) – Bombs in Baghdad and  northern Iraq killed at least 50 people yesterday, police  said, underscoring doubts about local forces’ ability to keep  Iraqis safe after U.S. troops pulled out of city centres.

The attacks in the north, where tensions between Arabs and  Kurds threaten to flare into Iraq’s next conflict, and in the  capital appeared to be part of an attempt by insurgents to  reignite sectarian fighting following the partial U.S. pullback.

Two suicide bombings in Tal Afar, a town in volatile Nineveh  province that is mainly home to minority Turkmen of the Shi’ite  Muslim faith, killed 34 people and wounded 60, police said. One suicide bomber detonated an explosives vest in the  historic centre of the town, 420 km (260 miles) northwest of  Baghdad, followed by another suicide attack just as people  responded to the first blast.

Nineveh and its main city Mosul have suffered a steady  drumbeat of attacks since June 30, when U.S. troops withdrew  from urban centres. It is an area where groups like al Qaeda  have taken advantage of tensions between Sunni Arabs, ethnic  Kurds and other minorities to sustain a stubborn insurgency.

In Baghdad, seven people were killed and 20 wounded by two  bombs in a market in Sadr City, a poor, Shi’ite Muslim area.  Later in the day, two roadside bombs targeting a police patrol  near a market in another Shi’ite area in the north of the  capital killed nine people and wounded 35, police said.