Nominations for all crude grades - Murban, Upper Zakum, Das and Umm Lulu - will be cut by 5% for all term lifters in July, the sources said, citing a letter to buyers dated May 28.
OPEC and allies led by Russia, a group known as OPEC+, agreed in April to a new supply pact from May 1 to shore up the market following a slide in demand caused by lockdowns to contain the new coronavirus.
OPEC+ plans to reduce output by a record 9.7 million barrels per day for May and June.
For May, ADNOC reduced the supply of its Murban and Upper Zakum crude by 15% and reduced the supply of its Umm Lulu and Das crude by 5%.
For June, ADNOC has told buyers of a cut of 20% in both Murban and Upper Zakum crude grades and a 5% cut in Das and Umm Lulu crude grades.