an Indonesian military jet

Tatang Sulaiman, Indonesia Armed Forces Spokesman, said a military helicopter crashed on Sunday in Central Sulawesi province, killing all 13 people on board.

He said the helicopter was carrying personnel to reinforce a police operation against Islamist militants operating in the district of Poso.

Sulaiman said military was suspecting that bad weather caused the crash.

He said Poso was the scene of deadly Muslim-Christian violence in 1999-2000, and the area has since become a known hotbed of militant activity.

Spokesman said last week police killed two suspected Islamist fighters from China’s Uighur ethnic group in a gunfight in Poso as part of an operation to crush a group led by a wanted militant named Santoso.

Sulaiman said more than 2,500 military and police personnel have been deployed in the area since January.