(Adds quotes, details on sanctions, background, new throughout)
WASHINGTON, Jan 12 (Reuters) - Iran will get some sanctions relief at the start of the implementation of the Nov. 24 nuclear deal but will not get all of it until the six-month implementation period ends, a senior U.S. official said on Sunday.
The official was one of several who briefed reporters about an agreement to implement the November nuclear deal between Iran and six major powers under which Tehran will receive limited sanctions relief in exchange for curbing its nuclear activities.
Assuming the International Atomic Energy Agency (IAEA), the U.N. nuclear watchdog, confirms Iran is carrying out the deal, the major powers would immediately suspend sanctions on Iran's petrochemical exports, on imports for its auto manufacturing sector and on its trade in gold and other precious metals.
According to U.S. estimates, the overall sanctions relief provided to Iran under the deal is worth about $7 billion. Of this amount, $4.2 billion is in the form of access to currently blocked Iranian revenues held abroad.
"Access to a portion of these funds will be linked to Iran's progress in completing the dilution process for 20 percent enriched uranium," said the official, referring to Iran's commitment to dilute half of its 20 percent enriched uranium to no more than 5 percent enriched uranium.
"Iran will not have access to the final installment of the $4.2 billion until the last day of the six-month period," the official said.
He declined to provide a detailed breakdown of how the $4.2 billion will be provided with Iran over the six months other than to say that it would be distributed "on a set schedule at regular intervals through out the six-month period." (Reporting by Arshad Mohammed; Editing by Leslie Adler, Bernard Orr)