ISIS use of chemical weapons in Iraq is alleged again

The United States is investigating whether the Islamic State of Iraq and Syria (ISIS) used chemical weapons, the White House said Thursday, following allegations that militants deployed chemical weapons against Kurdish forces in northern Iraq.

Alistair Baskey, a spokesman for the White House's National Security Council, said the U.S. is taking the allegations "very seriously" and seeking more information about what happened. He noted that ISIS had been accused of using such weapons before.

"We continue to monitor these reports closely, and would further stress that any use of chemicals or biological material as a weapon is completely inconsistent with international standards and norms regarding such capabilities," Baskey said in a statement.

Earlier on Thursday, Kurdish officials said their forces, known as Peshmerga, were attacked the day before near the town of Makhmour, not far from Ibril. Germany's military has been training the Kurds in the area, and the German Defense Ministry said some 60 Kurdish fighters had suffered breathing difficulties from the attack a telltale sign of chemical weapons use. But neither Germany nor the Kurds specified which type of chemical weapons may have been used.

Confirmation of chemical weapons use by ISIS would mark a dramatic turn in the U.S.-led effort to rout the extremist group from territory it has seized in Iraq and Syria. Although the U.S. and its coalition partners are mounting airstrikes against ISIS, they are relying on local forces like the Kurds, the Iraqi military and others to do the fighting on the ground.

Similar reports of chemical weapons use by ISIS had surfaced in July. But it's unclear exactly where the extremist group may have obtained any chemical weapons.

Following a chemical weapon attack on a suburb of the Syrian capital of Damascus in 2013that killed hundreds of civilians, the U.S. and Russia mounted a diplomatic effort that resulted in Syrian President Bashar Assad's government agreeing to the destruction or removal of its chemical weapons stockpiles. But there have been numerous reports of chemical weapons use in Syria since then especially chlorine-filled barrel bombs. The Organization for the Prohibition of Chemical Weapons, the global chemical weapons watchdog, has been investigating possible undeclared chemical weapons stockpiles in Syria.

Word of the White House's probe into possible chemical weapons use by ISIS came as President Barack Obama was vacationing with his family in Martha's Vineyard in Massachusetts