FILE - In this June 13, 2019 file photo, an oil tanker is on fire in the Gulf of Oman. The U.S. Navy is trying to put together a new coalition of nations to counter what it sees as a renewed maritime threat from Iran. Meanwhile, Iran finds itself backed into a corner and ready for a possible conflict. It stands poised on Friday, Sept. 6, 2019, to further break the terms of its 2015 nuclear deal with world powers. (AP Photo/ISNA, File)
TEHRAN, Iran Iran was poised Thursday to begin work on advanced centrifuges that will enrich uranium faster as the 2015 nuclear deal unravels further and a last-minute French proposal offering a $15-billion line of credit to compensate Iran for not being able to sell its crude oil abroad because of U.S. sanctions looked increasingly unlikely.