A bus carrying Kuwaitis returning from the funeral of a Shiite Muslim (searchreligious leader overturned in southern Iraq early Sunday, killing at least 15 people, the Interior Ministry said.

The bus was en route from the Shiite holy city of Karbala (search) when it overturned some 34 miles from the Iraq-Kuwait border, a ministry official said, speaking on condition of anonymity. He said details of the accident were sketchy and the number of injured was not known.

The official said there was no evidence of an attack. Highways in Iraq remain less than secure, and cars and buses have been targeted in the past.

The official Kuwait News Agency said the bus was part of a 13-vehicle convoy coming back from the funeral senior Shiite cleric Mirza Abdul-Rasoul al-Ihkaki, who recently died in Kuwait and was taken to Iraq for burial. KUNA quoted Interior Ministry officials, without giving their names.

The desert border between Kuwait (searchand Iraq was closed for 13 years after Saddam Hussein's regime invaded Kuwait in 1990 and occupied it for seven months. A U.S.-led coalition liberated the oil-rich state in the 1991 Gulf War, and the border was opened in April after Saddam's regime was ousted in the latest war.