LONDON—OPEC and non-OPEC states are discussing holding their ministerial meetings on oil output policy on July 10-12 in Vienna, a date range proposed by Iran, OPEC sources said on June 18.

OPEC, Russia and other producers have since Jan. 1 implemented a deal to cut oil output by 1.2 million barrels per day. The meeting is to decide whether to extend the pact and whether to adjust it.

The new suggestion is that the Joint Ministerial Monitoring Committee, an advisory panel, meets on July 10, followed by OPEC ministers on July 11 and the combined gathering of OPEC and non-OPEC producers on July 12, the sources said.