Daesh militants are "dead set" on using chemical arms and are likely to try them again as Iraqi forces advance on Mosul, a Pentagon spokesman said on Monday, a week after a rocket with a possible chemical agent landed near US troops, according to the Daily Mail.

The shell initially tested positive for a mustard agent, but two subsequent tests have been inconclusive and the device is undergoing further tests, Navy Captain Jeff Davis, a Pentagon spokesman, told reporters.

"We fully recognize this is something that Daesh has done before. They've done it many times, at least a couple dozen that we know of where they have launched crude makeshift munitions that are filled with this mustard agent," Davis said using an acronym for the group.

The rocket fired last Tuesday landed in an unpopulated area near Qayyara West base, several hundred yards from where hundreds of U.S. troops are working to prepare an airfield for an Iraqi offensive to recapture the city of Mosul. No one was hurt in the attack.

Source: MENA