Cairo: Average yields on Egypt's three- and nine-month treasury bills rose at an auction on Sunday, data from the central bank showed.

The average yield on the 91-day bill rose to 22.523 percent from 20.951 percent at the last similar auction on July 3 and the yield on the 273-day bill rose to 22.444 percent from 21.155 percent.

The central bank raised its key interest rates by 200 basis points last week for the second policy meeting in a row, confounding the expectations of economists who forecast rates were unlikely to change.

Foreign participation in the treasury bill auctions amounted to 3 billion Egyptian pounds ($168.26 million), the head of public debt at the Finance Ministry, Sami Khallaf, told Reuters.