Oil prices traded lower despite concerns over supply disruptions in the Middle East. The Arab coalition resumed air strikes against Houthi rebels in Yemen as a five-day humanitarian ceasefire expired late Sunday.

Islamic State captured the Iraqi city Ramadi.

Investors fear that rising oil prices could lift shale-oil production in the U.S.

Goldman Sachs lowered its crude oil price forecasts. It cut it Brent oil price forecast to $60-$65 for 2016-2019 and to $55 for 2020.

Comments by Iran's Deputy Oil Minister Rokneddin Javadi weighed on oil prices. He said that the country hopes its crude oil exports will return to 2.5 million barrels per day (pre-sanctions levels) within three months. Iran exports 1.1 barrels per day.

WTI crude oil for June delivery fell to $59.59 a barrel on the New York Mercantile Exchange. Brent crude oil for June decreased to $66.23 a barrel on ICE Futures Europe.