Yields fell to almost two-month lows on Friday as political discord in Washington sparked safety buying and on continuing concern about tensions between the United States and North Korea.

The bonds have now given back some of that rally as investors wait on a new catalyst to give the market direction.

"I think it's a pattern of consolidation we've been falling into," said Aaron Kohli, an interest rate strategist at BMO Capital Markets in New York. "We've been looking for a bit of yield bounce here just because we've done nothing but rally on very little news in the last couple of days."

Benchmark 10-year notes were last down 8/32 in price to yield 2.21 percent, up from 2.18 percent on Monday. The yields fell to 2.16 percent on Friday, the lowest since June 27.

Investors were focused on this week's annual central banking conference in Jackson Hole, which begins on Thursday, where Federal Reserve Chair Janet Yellen and European Central Bank President Mario Draghi are due to speak.

Many analysts and investors, however, do not expect that much new information will emerge at the conference.

Two sources have said Draghi will not deliver any new policy message at Jackson Hole, tempering expectations for the bank to start charting its course out of stimulus.

"You can get the market ready for tapering but you can do that in September and it's widely expected anyway, why add more fuel to the fire," said Kohli.

The Fed is expected to announce a plan to reduce its balance sheet at its September meeting.

Draghi will also speak at an event in Germany on Wednesday.

Stronger stock markets on Tuesday also reduced safety buying of US debt.