Oil prices lost Monday amid renewed uneasiness over Greece debt crisis after the country closed its banks to control capital outflow.

Greece worries battled the market after five-month reform-for- cash negotiations between Greece and international lenders collapsed without producing an agreement.

Banks and markets in Greece are closed until July 6, after Prime Minister Alexis Tsipras called for a referendum on July 5 on whether or not to accept the stringent terms set by international creditors.

The move triggered a series of reactions starting with the Eurogroup rejecting Greece's request for a loan extension. Without an agreement on June 30, Greece was unlikely to pay a 1.6-billion- euro (1.8 billion U.S. dollars) loan installment to the International Monetary Fund.

The latest development triggered investors' concerns that Greece is sliding toward defaulting on its government debt and worse, leaving the eurozone.

The U.S. benchmark, West Texas Intermediate for August delivery moved down 1.3 U.S. dollars to settle at 58.33 U.S. dollars a barrel on the New York Mercantile Exchange. The global benchmark, Brent crude for August delivery decreased 1.25 dollars to close at 62.01 dollars a barrel on the London ICE Future Exchange.