WASHINGTON • The Islamic State in Iraq and Syria (ISIS) is suspected of using chemical agents - said by some US officials to be mustard gas - in an attack on Kurdish fighters in northern Syria two weeks ago, US officials said last Friday.
If authenticated, the chemical attack would be an escalation of the more than year-long conflict under way in Iraq and Syria, and could increase pressure on the Obama administration to intervene more forcefully .
The Pentagon said on Friday that it also was looking into reports of another possible mustard gas attack this week on Kurdish fighters - this one in Makhmur, Iraq.
Kurdish media reports last Thursday quoted local officials as saying that mortar rounds fired at Kurdish positions in Makhmur may have contained mustard gas because the wounds to injured peshmerga fighters were different from those in a conventional attack.
"We've seen those reports, and we're taking them seriously," Colonel Patrick S. Ryder, a spokesman for the US Central Command, said last Friday. He added: "At this point, we really don't know what, if anything, may have been used."
He declined to say whether the United States has sent independent inspectors to verify the attacks.
The question is complicated by history. Kurds have suffered chemical attacks in the past, but since 2002, various Kurdish officials seeking Western support have highlighted stories of chemical attacks and chemical weapons stocks that were never confirmed.
But on Friday, two US officials said the defence and intelligence community had come to believe that mustard gas was used two weeks ago in the northern Syria attack. That view, one official said, had prompted assessments that the Makhmur report last week was "plausible".
NEW YORK TIMES