A rocket hit a downtown Baghdad park Thursday, killing two people as American and Iraq (web|news) i forces battled Shiite militants believed responsible for many such attacks. The U.S. military said that 17 militants had been killed since Wednesday in clashes around Baghdad. The rocket, which also wounded six people, was the second in three days to land in downtown parks apparently after failing to reach the U.S.-protected Green Zone, which includes the U.S. Embassy and key Iraqi government offices.

A rocket hit and destroyed some playground equipment in another park Tuesday.

Meanwhile, a bomb went off on a minibus Thursday in Baghdad's eastern Zayona neighborhoos, killing two passengers and injuring five, police said.

U.S. forces have increased air power and armored patrols in an attempt to cripple Shiite militia influence in Sadr City, a slum of 2.5 million people and the Baghdad base for the Mahdi Army led by anti-American cleric Muqtada al-Sadr.

Nine militants were killed in two American missile attacks in the New Baghdad neighborhood early Thursday, the U.S. military said. U.S. soldiers killed one of two militants who were planting a roadside bomb in the northern Baghdad suburb of Kazimiyah, the military said.

Seven other militants were killed in clashes around Baghdad Wednesday, the U.S. military said. Iraqi health officials said that at least seven people were killed and 20 wounded in clashes in Sadr City late Wednesday. It was not clear whether any militants were among them.

Fighting with Shiite militants started in late March after the Iraqi government launched a crackdown on militias and armed gangs in the southern city of Basra, including some groups Washington says have links to Iran. Tehran denies the allegations.

Some residents of Sadr City claimed Thursday that Iraqi soldiers warned them to leave their houses and go to nearby soccer stadiums for security reasons. The U.S. military denied the claim and called it as a "rumor."

UNICEF says about 6,000 people have been forced to flee their homes in Sadr City.

A former leader of al-Qaida (web|news) in Iraq, Mulla Nadhim al-Jibouri, was wounded in a suicide attack in the town of Duluiyah, 45 miles north of Baghdad, Iraqi police said. Al-Jibouri was a local commander of Awakening Council fighters, Sunnis who once sided with al-Qaida but now work with U.S.-led forces.

Two Iraqi policemen were also wounded in the attack, according to a police official speaking on condition of anonymity because he was not authorized to speak to the media.

Iraqi soldiers shut down a Baghdad radio station, al-Aahad, run by the Sadrists after raiding offices of the station, police said.

In the southeastern Shiite city of Kut, gunmen stormed the Technical Institute and abducted a professor, Nuri Kamil Khanjar, local police said. It was not clear why Khanjar was kidnapped.

Five suspected al-Qaida members, including a Moroccan national, were killed in an operation in the northern city of Samarra on Wednesday, police said.

Four other Sunni insurgents were killed in the province of Salahuddin also Wednesday when they attacked a checkpoint manned by Awakening Council fighters, the military said Thursday.