Iraqi officials say a suicide bomber has detonated a truck filled with explosives and chlorine gas near the western Iraqi city of Ramadi.  At least 27 people were killed and dozens more injured and sickened.  From Baghdad, VOA's Margaret Besheer has more.

Iraqi police say the truck bomber targeted a police checkpoint a few kilometers from the Sunni city of Ramadi, in the volatile western province of al-Anbar.

Local council member Muhammad Nattah told Iraqi television that the bomber struck at around 11 in the morning in a densely populated neighborhood. He said the truck was loaded with explosives and chlorine, and many casualties were taken to a hospital in Ramadi.

Recently, insurgents have been using chlorine in their attacks, which when released into the atmosphere sickens those who come in contact with the toxic gas.

Officials accuse al-Qaida in Iraq of perpetrating the attacks, which have occurred in mostly Sunni western Iraq, where many tribal leaders have withdrawn their support for the terrorist group.

Meanwhile, in the southern city of Diwaniyah, a stronghold of the Shiite Mahdi Army, Iraqi and U.S. forces conducted security sweeps of the city.

"This morning, Iraqi and coalition troops launched Operation Black Eagle down in the town of Diwaniyah in order stem rising militia violence," explains U.S. military spokesman Lieutenant Colonel Christopher Garver.

Residents said a curfew had been imposed and that troops were blocking streets and conducting house-to-house searches.

Khaleel Jaleel Hamza, the governor of Diwaniyah, said Iraqi and U.S. forces clashed with armed groups from the area, but he did not have any information on casualties.

Lieutenant Colonel Garver said the operation would continue.

"The operation will continue until that part of Diwaniyah has been cleared and the militia influence has been either driven out or the militia members acting against the will of the Iraqi people are either captured or killed," he added.

Meanwhile, another journalist has been killed.  Radio Free Iraq reports its correspondent, Khamail Khalaf, was found dead in Baghdad Thursday. She had been missing for two days amid fears she had been kidnapped.  More than 150 members of the news media have been killed in Iraq since the war began in 2003.