GENEVA, Nov 24 (Reuters) - Iran will get access to $4.2 billion in foreign exchange as part of an agreement under which it will curb its nuclear program in exchange for limited sanctions relief, a Western diplomat said on Sunday.

The diplomat provided no further details of the agreement, which was struck after four days of negotiations between Iran and six major powers: Britain, China, France, Germany, Russia and the United States. (Reporting By Arshad Mohammed)