The US has indicated a
shift in its campaign against Islamic State (IS) militants in Iraq and Syria, as
well as the use of direct ground raids.
Defence
Secretary Ashton Carter said there would also be more air strikes against
"high-value targets".
Observers
say his remarks reproduce acknowledgment of the lack of progress in defeating
the militant group.
Individually,
Iran says it is considering whether to attend international talks in Vienna
this week on Syria's war.
Earlier,
the US said Iran - an ally of Syria's President Bashar al-Assad - was being
invited to the talks for the 1st time.
Foreign
ministry spokesperson Marzieh Afkham said "Iran's sharing is under
discussion", Iranian news agencies reported.
Mr.
Carter's remarks, made to the Senate Armed Services Committee, come a week
after US-Iraqi forces rescued dozens of hostages held by IS in Iraq.