ISTANBUL (Reuters) - U.S.-led coalition jets and Turkish artillery killed 13 Islamic State militants in Syria on Saturday, military sources said.

The Turkish army fired howitzers at 32 targets in northern Syria to take out Islamic State weapon systems as the militants prepared to shell sites across the Turkish border, the sources told Reuters.

About 20 people have been killed inside Turkey this year by Islamic State shelling across the border. NATO member Turkey is a member of the U.S.-led coalition fighting Islamic State.