Oil is cheaper on the background of continuing decline in consumer confidence in the American economy and the deepening debt crisis of the euro zone, affecting the consumption of oil.

Published on Tuesday, the data research firm Conference Board showed that consumer confidence in the U.S. economy in May fell to 64.9 points from the revised downwards in the figure for April 68.7 points. These differed from the expectations of analysts, who, in contrast, forecast growth rate to 69.5 points from 69.2 points unrevised month earlier.

Tensions between the West and Iran persists, as talks on Tehran's nuclear program last week, ended in nothing.

In Europe, investors continue to wonder whether there will be Greece in the euro area, and to monitor the state of the banking sector in Spain.

Crude for July delivery dropped to $90.37 a barrel on the New York Mercantile Exchange.

Brent oil for July settlement slipped 84 cents, or 0.8 percent, to $106.27 a barrel on the London-based ICE Futures Europe exchange.