The logo of the Organization of the Petroleum Exporting Countries (OPEC) is seen inside their headquarters in Vienna, Austria December 7, 2018. REUTERS/Leonhard Foeger

VIENNA (Reuters) - Iran gave OPEC the green light on Friday to cut oil output by around 0.8 million barrels per day from 2019, an OPEC source said.

OPEC will later ask non-OPEC producers to contribute an additional 0.4 million bpd to the cuts, the source said.