West Texas Intermediate futures for July delivery, which expires today, little changed at $59.99 (+0.03%) and. Brent crude for August slightly advanced by 0.13% to $63.10 a barrel amid hopes for a deal between Greece and its lenders as the country's Prime Minister Alexis Tsipras said he prepared a new package of reforms, which will be discussed today at the emergency meeting of the euro zone leaders.

However, soon Iran, OPEC's fifth-largest producer, may add to the global supply glut issue as a June 30 deadline on nuclear deal approaches. In case sanctions are lifted the country may double its exports. Iran is currently allowed to export about 1 million barrels a day.