The U.S. government debt sector recorded a 2.88 percent total return in January as the 30-year bond yield set a series of record lows on worries about weakening global growth.

Last month's return on Treasuries was the biggest since a 3.54 percent jump in December 2008, according to an index compiled by Bank of America Merrill Lynch.

"We are giving back some of the gains from the short-covering rally last week," said Suvrat Prakash, interest rate strategist at HSBC Securities USA in New York.

Selling also came from some fund managers reallocating money into stocks from bonds at the start of a new month and on expectations of a relatively heavy supply of higher-yielding corporate bonds in February, analysts said.

Apple Inc. planned to raise \\$5 billion in the bond market on Monday, while investors await a likely \\$27 billion bond deal from Actavis, according to IFR, a unit of Thomson Reuters.

The decline in bond prices was capped by disappointing data on domestic manufacturing and construction spending that supported the view of a slowing U.S. economic expansion.

The latest economic figures also raised bets the Federal Reserve would abandon possible plans to end its near zero interest rate policy in 2015 as policy-makers are monitoring risks from sluggish price growth at home and troubling financial developments in Europe.

The Institute for Supply Management (ISM) said its index of national factory activity fell to 53.5 in January from 55.1 in December. The reading was shy of expectations of 54.5, according to a Reuters poll of economists.

The U.S. Commerce Department said construction spending rose at an annualized rate of 0.4 percent in December, falling short of an expected 0.7 percent increase.

On the open market, benchmark 10-year Treasuries notes were little changed in price with a yield of 1.676 percent. On Friday, the 10-year yield fell to 1.637 percent, a level not seen since May 2013.

The 30-year bond was down 1/32 in price with a yield of 2.261 percent, up on the day. On Friday, the 30-year yield hit a record low of 2.221 percent, according to Reuters data.