ABUJA, Feb 7 (Reuters) - Exxon Mobil on Thursday declared force majeure on Nigeria's benchmark Qua Iboe crude oil exports due to pipeline repair work, the company's local unit said, cutting output from Africa's top producer. Nigeria is among the world's top 10 crude exporters and usually ships around 2 million barrels per day, supplying the United States, China and India with its light oil. Qua Iboe is Nigeria's largest crude oil stream with exports, before this announcement, expected to be around 400,000 bpd in February, according to shipping schedules. At least three cargoes due to be shipped in February have already been pushed back to March, traders said last month. "We are working to minimize down-time and have notified appropriate regulatory agencies and purchasers. We regret any inconveniences this may cause our customers," a statement from Mobil Nigeria said. Exxon only lifted a three-week long force majeure on Qua Iboe on December 10 last year, which was put in place due to outages caused by flooding and oil spills. Fellow oil majors Shell, Total and Eni declared force majeure on Nigerian oil and gas exports late last year as oil theft and flooding caused serious outages. Oil theft is a major problem in the winding creeks and waterways of the Niger Delta, where it is easy to conceal boats and illegal refineries in the dense mangroves. Nigeria estimates around 150,000 bpd is stolen, much of which is sold abroad.