U.S. military officials say a gunbattle in a western Iraqi border town has killed five Marines and 16 insurgents.

Officials say the fighting took place in Ubaydi, where U.S. forces have been trying to clear insurgents from areas near the Syrian border.

Near Baghdad, officials said an improvised explosive device killed an American soldier Tuesday.

Meanwhile, Iraq's main Sunni Arab political party (the Iraqi Islamic Party) is demanding an international probe of allegations that Sunni prisoners were abused and possibly tortured at a secret Interior Ministry-run jail in Baghdad.

U.S. military officials have offered to support an Iraqi investigation into the prison.

Some Sunnis accuse a Shi'ite militia (Badr Organization) of running the prison.  The Shi'ite group denies any involvement.

U.S. troops said there were some 170 prisoners in the facility when they discovered it Sunday.

Some information for this report provided by AP, Reuters.