Gunmen killed a Kurdish journalist near the northern city of Kirkuk, a police official said Tuesday.

Soran Mama Hama, a reporter for the Kurdish-language magazine Leven, was shot late Monday in the Rasheed Awa village, where many Kurds were forced to relocate when Saddam Hussein sent thousands of Arabs into the oil-rich Kirkuk area to dilute the presence of Kurds and others.

Kirkuk police Brig. Gen. Sarhat Qadir said the motive for the slaying of the 23-year-old journalist was not immediately known.

Qadir said gunmen killed the journalist. But the U.S. military gave a differing account, saying he was killed by a bomb. The reason for the conflicting reports was not immediately clear.

Reporters Without Borders said Hama had often covered government corruption for the magazine. He had written an article in the latest issue that was about the involvement of Kurdish officials in prostitution rings, according to the Paris-based advocacy organization.

"He wrote hard-hitting articles about local politicians and security officials and had received threats from people telling him to stop his investigative reporting. The authorities should therefore give priority to the theory that he was killed because of his work," the group said.

The magazine said the killing "took place in a Kurdish area that is supposedly away from the reach of the terrorist gunmen."

It said it held "the Kurdistan presidency, government and parliament accountable" for the killing and demanded an investigation.

"We call upon the international organizations on the top of which is the U.N., those who care about journalism and journalists and human rights organizations to investigate the killing," the statement said.

It warned that independent journalism in Kurdistan is in danger because journalists there are constantly "intimidated by invisible hands working through assassinations."

The head of the Kurdish Journalists Union in Kirkuk, Latif Fatih Faraj, blamed the killing on gangs seeking to silence reporters who want to expose corruption.

"This criminal act is to halt the free speech of independent journalists in Kirkuk," he said. "If the government can't protect Kurdish journalists in Kirkuk, we might advise them to withdraw from this city."

Kirkuk — a city of Kurds, Arabs, Turkmen and others — is one of the most difficult ethnic puzzles facing Iraqi leaders.

Kurds see the area as part of their historical homeland and are pushing the government to hold a referendum in Kirkuk on whether to join the semiautonomous Kurdish region. Kurdish objections, meanwhile, are blocking parliament from clearing the way for important provincial elections scheduled for later this year.

The New York-based Committee to Protect Journalists says at least 129 journalists and 50 media support workers have been killed since the U.S. invasion in 2003, not including the most recent death.