The United States expects Islamic State to use crude chemical weapons as it tries to repel an Iraqi-led offensive on the city of Mosul, U.S. officials say, although adding that the group’s technical ability to develop such weapons is highly limited.

U.S. forces have begun to regularly collect shell fragments to test for possible chemical agents, given Islamic State’s use of mustard agent in the months before Monday’s launch of the Mosul offensive, one official said. Continue Reading.