Treasuries rose Monday, and the 10-year note gained ground for the first time in six sessions. Investors appeared to be rotating out of stocks and into bonds as worries built about biological terrorism in the U.S., pressuring the equities averages.

Around 11 a.m. EDT, the two-year note was up 2/32 to 99 31/32, yielding 2.77%. The five-year was up 6/32 to 103 10/32, dropping the yield to 3.83%. The 10-year was climbing 10/32 to 102 29/32, yielding 4.63%, and the 30-year bond was up 13/32 to 99 22/32, with a yield of 5.40%.