Oil prices traded higher on a stronger U.S. dollar. The U.S. dollar declined against the other currencies on the uncertainty over the Greek debt talks. Yesterday's debt talks were unsuccessful. The European Commission's Valdes Dombrovskis said that the Eurogroup is ready to continue the debt talks.

European Council President Donald Tusk called the Eurozone leaders' meeting for Monday at 17:00 GMT in Brussels.

Investors closely monitored the situation in Saudi Arabia. They are concerned that Saudi Arabia may increase its oil production despite the global oil glut if oil demand rises. Saudi Arabian oil minister Ali al-Naimi said that he was optimistic about the oil market in coming months.

The prospect of a deal over Iran's nuclear program, which would allow Iran to increase oil exports, also weighed on oil prices.

WTI crude oil for July delivery decreased to $59.35 a barrel on the New York Mercantile Exchange.

Brent crude oil for July fell to $62.79 a barrel on ICE Futures Europe.