London (AFP) - Failure to secure a deal with Iran could mean a nuclear arms race in the Middle East, the foreign secretary warned in comments released on Thursday.
"I remain clear that no deal is better than a bad deal. But we should also be clear-eyed about the alternative," Foreign Secretary Philip Hammond said in a speech in London.
"No deal means no restrictions on enrichment, no restrictions on research and development, and no independent monitoring or verification. It means a fundamentally more unstable Middle East, with the prospect of a nuclear arms race in the region."
His comments came as US Secretary of State John Kerry arrived in Switzerland for down-to-the-wire talks with Iranian Foreign Minister Mohammad Javad Zarif.
The negotiations, which include Britain, France, Germany, Russia and China, aim to stop Tehran developing nuclear weapons in return for an easing of crippling sanctions. Iran insists it nuclear ambitions are peaceful.
US officials on Wednesday said that a deal was in sight and could be achieved by the March 31 deadline, in what would be the cap on more than a decade of painstaking negotiations.
Hammond said that a deal would require "difficult decisions" on all sides but urged for every effort to be made to reach an agreement.
"So now is the time, with our key allies, to build on the recent momentum, to press Iran where differences remain, and to strain every sinew to get a deal over the finishing line," Hammond said.
"The door to a nuclear deal is open, but Iran must now step through it."