(Adds total foreign holdings of Egyptian treasuries)
CAIRO, June 21 (Reuters) - Average yields on Egypt's three- and seven-year treasury bonds were mixed at an auction on Wednesday, while average yields on six-month and one-year treasury bills rose at another auction on the same day, data from the central bank showed.
The average yields on the three-year bonds rose to 18.382 percent from 18.271 percent at the last auction on June 12, while the seven-year bond yields dipped to 18.346 percent from 18.377 percent.
At another auction on Wednesday, the average yield on the 182-day bill rose to 20.413 percent from 20.384 percent at the last sale on June 15, while the yield on the 364-day bill rose to 20.390 percent from 20.307 percent at a previous auction.
Foreigners have been buying up Egyptian government debt since the central bank hiked its key interest rates by 200 basis points last month.
Foreign holdings in Egyptian government securities rose seven percent in the past week to hit 164 billion Egyptian pounds ($9.09 billion) the head of public debt at Egypt's Finance Ministry, Sami Khallaf, said on Wednesday. ($1 = 18.0500 Egyptian pounds) (Reporting by Arwa Gaballa and Eric Knecht, editing by Pritha Sarkar)