LONDON, Feb 5 (Reuters) - OPEC oil output fell in

January for a second month, a Reuters survey found, as a drop in

exports from Nigeria and Iran offset a rebound from the United

Arab Emirates where field maintenance had curbed output in

December.

The Organization of the Petroleum Exporting Countries pumped

26.53 million barrels per day last month, down 50,000 bpd from

December's revised total, the survey showed on Wednesday, with

Nigeria and Iran posting the largest drops.

The modest decline in output came as the wider OPEC+ group

is keeping production cuts in place until the end of March due

to global demand concerns and rising output outside the group.

OPEC+ on Monday decided to stick with its plan to start raising

output in April.

Nigerian production slipped by 60,000 bpd, the survey found,

reflecting lower exports, although domestic usage is increasing

as the Dangote refinery ramps up.

Iran's output, which hit the highest since 2018 last year

despite U.S. sanctions, also fell by 60,000 bpd, the survey

found. It may soon be curbed by tighter sanctions from the

administration of U.S. President Donald Trump, Goldman Sachs ( GS ) and

other analysts have forecast.

Output in OPEC's top two producers, Saudi Arabia and Iraq,

edged lower, the survey found.

OPEC's biggest rise, of 90,000 bpd, came from the UAE, the

survey found. A source said partial field maintenance continued

in January, having started in December.

While the survey indicates the UAE and Iraq are pumping

below their targets and December data provided by OPEC's

secondary sources puts them not far above, other estimates such

as those of the International Energy Agency suggest they are

pumping significantly more.

Libya's output rose by 40,000 bpd, continuing a recovery

after the resolution of a dispute over control of the central

bank that had led to production cuts. The country is exempt from

OPEC+ agreements to limit output.

The Reuters survey aims to track supply to the market and is

based on flows data from financial group LSEG, information from

other companies that track flows such as Kpler, and information

provided by sources at oil companies, OPEC and consultants.

(Additional reporting by Ahmad Ghaddar. Editing by Mark Potter)