At least eight people were killed by a female suicide bomber in a crowded market north of Baghdad in volatile Diyala province. The U.S. military this month launched a new offensive in Diyala aimed at driving out al-Qaida in Iraq and other Sunni extremists. VOA's Deborah Block has more from Baghdad.

The woman wearing a vest lined with explosives blew herself up in the small, mainly Shi'ite town of Khan Bani Saad near Baquba, capital of the religiously-mixed province.

There have been several female suicide attacks in Iraq in the last three months, all in Diyala province.

Although female suicide bombings are rare in Iraq, extremists have been using women more frequently in recent months. U.S. officials say this indicates the militants are running short of male volunteers. But it might be that al-Qaida in Iraq believes women are less likely than men to be searched and that explosives are easier to conceal under women's clothing.

The U.S. military announced that one of the key al-Qaida in Iraq leaders in Diyala, Abu Layla al-Suri, also known as Abu Abd al-Rahman, was killed in a military operation on December 30 near Muqdadiyah, north of Baghdad.

U.S. military spokesman Major General Kevin Bergener says a coalition operation known as "Phantom Phoenix" is focusing on Diyala province. He said concerned local citizens in Diyala are working with Iraqi security forces and tribal and government leaders to improve security.

"And so there is a multi-pronged approach underway to improve security there," said General Kevin Bergener. "It is focused on offensive operations involving both coalition and Iraqi forces, and it is also involved in encouraging Iraqi citizens at the local level to help contribute to that. And it is making a difference."

The Iraqi army said 64 suspects were arrested during one of its Diyala operations on Tuesday.

The government is imposing a curfew on Diyala, Baghdad, and 10 southern provinces beginning Thursday through the 10-day Shi'ite Muslim religious holiday, Ashura.