The Organization of the Petroleum Exporting Countries (OPEC) said on Wednesday that demand for its crude remains unchanged this year, but it expects the current oversupply will ease in the second half of the year.

"The current oversupply in the market is likely to ease over the coming quarters," the OPEC said.

The OPEC estimated oil demand growth in 2015 at 1.18 million barrels a day. It expects the rise in non-OPEC crude oil output to remain unchanged at 680,000 barrels a day in 2015 - one-third of the increase recorded in 2014.

The OPEC also said that oil output increased by 24,000 barrels per day due to rises in Iraq, Angola and Saudi Arabia. Iraq produced 3.8 million barrels a day in May, while Saudi Arabia produced 10.333 million barrels.