BAGHDAD, Iraq — U.S. forces killed nine suspected al-Qaida in Iraq insurgents during a raid in a rural area south of Baghdad today, and more than 1,000 Iraqi soldiers launched a military operation in northern Iraq with American air and artillery support.

Deadly attacks continued in the capital, with suspected insurgents and militias using guns, bombs and mortar shells to kill 15 Iraqis. And the U.S. Army announced that four soldiers had died in combat this week.

In Youssifiyah, a rural area 12 miles south of Baghdad, U.S. soldiers were conducting a raid and telling civilians to exit buildings when they saw several armed men in a nearby wooded area, the military said. The soldiers called in air support that killed nine suspected al-Qaida in Iraq insurgents, several of whom were wearing explosive vests, the military said.

The soldiers detained nine other suspected insurgents during the raid.

The military also said that more than 1,000 Iraqi soldiers had begun conducting a military operation aimed at clearing several villages of suspected insurgents and their weapons caches near the northern city of Kirkuk.

The cordon-and-search operation, which began Wednesday, relied on the support of U.S. air and artillery.

Meanwhile, Iraq's higher education minister said today that as many as 80 people kidnapped from his ministry's office remain captive, disputing government claims that most have been released.

Higher Education Minister Abed Theyab said 70 of 150 hostages had been released and those freed "were tortured and suffered a lot."

Dozens of people were taken Tuesday in a brazen raid on the central Baghdad office that handles academic grants and exchanges.

Basil al-Khatib, a spokesman for Theyab, said people freed after the kidnapping Tuesday told officials that: "Some of the hostages were tortured and killed."

Government ministries have given wildly varying figures on the number of people seized, with reports ranging from a high of about 150 to a low of 40 to 50.