NEW YORK, Aug. 17 (Xinhua) -- Oil prices gained on Monday as investors weighed multiple factors.

The West Texas Intermediate (WTI) for September delivery gained 88 cents to settle at 42.89 U.S. dollars a barrel on the New York Mercantile Exchange, while Brent crude for October delivery climbed 57 cents to close at 45.37 dollars a barrel on the London ICE Futures Exchange.

"Oil prices are getting off to a more positive start to the week after Friday saw them come under pressure following the IEA's (International Energy Agency) downward revisions of demand," Eugen Weinberg, energy analyst at Commerzbank Research, said in a note on Monday.

The analyst said a weak dollar and a further decline in U.S. drilling activity were among the reasons that lent some support.

The U.S. dollar index, which measures the greenback against six major peers, decreased 0.25 percent to 92.8591 in late trading on Monday.

Oilfield services company Baker Hughes said Friday that U.S. oil rig count fell by another four to 172 last week.

For the week ending Friday, WTI rose 1.9 percent, while Brent gained 0.9 percent.

(Photo: Agencies)