Oil prices climbed on Thursday in choppy trading after separate surveys indicated crude output in major oil producers declined.

The Organization of the Petroleum Exporting Countries (OPEC) pumped 32.68 million barrels per day (bpd) last month, down 460,000 bpd from November and the largest month-on-month drop since January 2017, said a Reuters survey on Thursday.

Meanwhile, a survey by the Bloomberg showed oil output from OPEC fell 530,000 barrels a day to 32.6 million a day in December, the sharpest pullback since January 2017.

January also marked the beginning of output cuts by OPEC and its allies.

At a meeting in December, OPEC and some other major oil producers, including Russia, pledged to cut production by 1.2 million bpd, effective from January 2019.

The prospects for further declines in crude output and concerns over possible shrinking demand for oil due to a slowing global growth caused market volatility on Thursday, experts noted.

The West Texas Intermediate for February delivery gained 0.55 U.S. dollar to settle at 47.09 dollars a barrel on the New York Mercantile Exchange, while Brent crude for March delivery increased 1.04 dollars to close at 55.95 dollars a barrel on the London ICE Futures Exchange.