The prices of the 10-year Treasury note rose 53.1 cents per $100 invested. Its yield, which moves in the opposite direction, fell to 3.63 percent from 3.71 percent late Thursday.
Bonds had rallied earlier as pressure on prices abated from this week's auctions, which put $72 billion of new debt into the market. The Treasury sold $32 billion in three-year notes on Tuesday, $24 billion in 10-year notes on Wednesday and $16 billion in 30-year notes on Thursday.
"It's a relief rally," said Josh Stiles, an analyst at IDEAGlobal.com.
Uncertainty surrounding Mubarak's next move also had led traders to flock to the safety of Treasurys and dump riskier investments like stocks. The yield on the 10-year note had fallen as low as 3.62 percent in morning trading.
Bond prices largely have been falling since November as better reports on the economy came out.
Investors are looking ahead to next week's economic reports including retail sales on Tuesday, the producer price index on Wednesday and the consumer price index on Thursday, which is a key marker of inflation. If inflation rises too quickly, the central bank likely will raise short-term interest rates to fight it.
The Federal Reserve Bank of New York bought $7.4 billion in Treasurys Friday as part of its ongoing $600 billion bond-buying program intended to lower interest rates, increase spending and boost the economy.
In other trading, the price of the 30-year Treasury note increased $1.18 per $100 invested, while its yield slipped to 4.69 percent from 4.77 percent. The yield on the two-year note was unchanged at 0.84 percent.
The yield on the three-month T-bill was unchanged at 0.11 percent. Its discount was 0.12 percent.