In Iraq today, three bomb blasts left more than 75 dead and 145 wounded. The attacks occurred as U.S. and Iraqi forces step up a massive security operation aimed at stabilizing the capital. Thousands have died in Baghdad in the sectarian conflict between Sunnis and Shiites.
But it's not the only city in Iraq with such an explosive mix. In the north, Kirkuk has often been called a tinderbox because of simmering tensions between its Arab, Kurdish and Turkmen residents.
The city has been relatively calm over the past four years compared to Baghdad, but there are fears that ethnic tensions could escalate ahead of a planned referendum on whether Kirkuk should become part of Iraq's autonomous Kurdish region. Kirkuk also sits on some of the Iraq's richest oil deposits.
Security forces operating in Kirkuk have established a tenuous calm in the city.