FILE PHOTO: Iran's national flags are seen on a square in Tehran February 10, 2012, a day before the anniversary of the Islamic Revolution. REUTERS/Morteza Nikoubazl/File Photo

BERLIN (Reuters) - European and U.S. officials are planning to meet in Berlin in March for talks on Iran’s 2015 nuclear deal with world powers, a German Foreign Ministry source said on Wednesday.

Another European diplomat said the meeting would take place on March 15.

Hailed as key to stopping Iran from building a nuclear bomb, the deal lifted economic sanctions in exchange for Tehran limiting its nuclear program. It was signed by the United States, China, France, Russia, Britain, Germany and the European Union.

But U.S. President Donald Trump has long railed against the deal for reasons including its limited duration and the fact it does not cover Iran’s ballistic missile program.

Trump has threatened to pull out of the agreement unless European allies help “fix” it with a follow-up accord.

Britain, France and Germany have called on Trump to uphold the pact. [nL8N1P61V9]

Iran says its nuclear program is only for peaceful purposes and that it will stick to the accord as long as the other signatories respect it but will “shred” the deal if Washington pulls out.