An oil tanker sought by the U.S. over allegedly circumventing sanctions on Iran was hijacked on July 5 off the coast of the United Arab Emirates, a seafarers welfare organization said Wednesday. It wasn't immediately clear what happened aboard the Dominica-flagged MT Gulf Sky, though its reported hijacking comes after months of tensions between Iran and the U.S. David Hammond, the CEO of the United Kingdom-based group Human Rights at Sea, said he took a witness statement from the captain of the MT Gulf Sky, confirming the ship had been hijacked.