CAIRO, Jan 15 (Reuters) - Yields on Egypt's three-month and nine-month treasury bills rose at an auction on Sunday, central bank data showed.

Yields on the 91-day bill increased to an average of 19.017 percent from 18.889 percent at the previous auction. Yields on the 266-day bill rose to 20.191 percent from 19.858 percent at a similar auction.

(Reporting by Eric Knecht; Editing by Catherine Evans) ((ahmed.aboulenein@thomsonreuters.com; +20 2 2394 8097; Reuters Messaging: ahmed.aboulenein.thomsonreuters.com@reuters.net))