A U.S. military helicopter has crashed southeast of the Iraqi capital, Baghdad, killing two coalition soldiers and injuring 12 others.

The U.S. military says initial reports indicate Tuesday's crash near the town of Salman Pak was not the result of hostile fire. It did not specify the nationality of the casualties or the type of helicopter. The crash is the first by a U.S. helicopter in Iraq since August.

In other developments, Iraqi authorities have found a mass grave in southern Iraq containing remains of at least 13 people killed during the 1991 Shi'ite uprising against Saddam Hussein. Officials say the gravesite was found by a farmer north of the city of Najaf.

Separately, Iraqi Prime Minister Nouri al-Maliki is blaming the country's Sunni Vice President, Tariq al-Hashemi, for delays in the implementation of laws adopted by Iraq's parliament.

In an interview with London-based newspaper Al-Hayat published Tuesday, Mr. Maliki says Al-Hashemi is refusing to approve laws that must be ratified by Iraq's three-man presidential council, of which Al-Hashemi is a member.

Iraqi Shi'ites launched the 1991 revolt after a U.S.-led coalition drove Saddam's army out of Kuwait in the first Gulf War. Saddam loyalists crushed the rebellion, killing tens of thousands of Shi'ites.

Also today, the U.S. military said coalition forces killed 17 terrorists and detained 16 suspects in operations across Iraq since Sunday.

And a car bomb blast in Baghdad's Baiyaa district killed one person and wounded six others.

Some information for this report was provided by AFP, AP and Reuters.