Qatar and Kuwait have told the United States that they will join a U.S.-led naval coalition in the Gulf which was established in response to a series of attacks on oil tankers, a U.S. military official said on Monday.

"Qatar and Kuwait have already told us they are going to join, so it is just a matter of time," U.S. Army Colonel John Conklin, chief of staff of the coalition, said.

The coalition, based out of Bahrain, is known as the International Maritime Security Construct (IMSC)

(Reporting by Idrees Ali Editing by Chizu Nomiyama)