Oil prices ended slightly higher on Monday after last week's sharp losses.

Oil prices were under pressure last week as data showed U.S. oil production had increased. Oilfield services firm Baker Hughes said on Friday that the number of active U.S. rigs drilling for oil was up seven to 763 last week.

Analysts said although the oil prices rebounded on Monday, the investors are still very concerned about rising U.S. drilling activity, as it would offset some of the output-cut efforts from major oil producers.

The West Texas Intermediate for August Delivery added 17 cents to settle at 44.40 dollars a barrel on the New York Mercantile Exchange, while Brent crude for September delivery gained 17 cents to close at 46.88 dollars a barrel on the London ICE Futures Exchange.