U.S. crude prices rebounded on Monday after six straight days of declines on speculation of more sanctions against Iran from Western countries ahead of another round of Iran nuclear talks on May 23.

The head of United Nations' International Atomic Energy Agency pressed Iran over inspections during a visit to Tehran on Monday, which would have an impact on the six-power meeting later this week. But there was no signs of breakthrough deal. Speculations of more sanctions against Iran pushed the prices up.

Enterprise Products Partners LP and Enbridge Inc. started shipping oil on May 19 through the 150,000 barrel-a-day Seaway pipeline from Cushing, Oklahoma, to Houston-area refineries, the companies said in a statement. Stocks pressure at the WTI delivery point eased, providing further supports.

Besides, comments from China's Premier Wen Jiabao boosted expectation of more stimulus measures to bolster the slowing economy in the world's second largest oil consumer.

In Europe, concerns over Greece partly eased after the Group of Eight industrialized nations said at the summit over the weekend that they support Greece remaining in the euro zone. And polls showed that Greece's conservative parties gained more supports, generating hopes of political stability in the debt-ridden country.

Equities both in Europe and Wall Street went higher, which also helped boost market sentiment.

Light, sweet crude for June delivery rose 1.09 dollars, or 1.19 percent to settle at 92.57 dollars a barrel on the New York Mercantile Exchange. In London, Brent crude for July delivery also rose and last traded around 109 dollars a barrel.