SINGAPORE, Jan 6 (Reuters) - The world's top oil exporter, Saudi Arabia, has cut February's official selling price (OSP) for all grades of crude it is selling to Asia by at least $1 a barrel, three sources with knowledge of the matter said on Thursday.

The producer set the February OSP for Arab Light crude at $2.20 a barrel above the average of Oman/Dubai quotes, down $1.10 from the previous month, they said. (Reporting by Florence Tan; Editing by Muralikumar Anantharaman)