U.S. Treasury prices rose Wednesday, driving yields lower, as investors sought the safety of government debt amid renewed concerns about global economic growth and the looming U.S. fiscal cliff.

The yield on the benchmark 10-year Treasury note fell to 1.63% in late trading, down from 1.67% on Tuesday. The 30-year bond yield declined to 2.78%. Shorter-term Treasury yields also moved lower, with the 2-year note yielding 0.26%.

Worries about the global economy were stoked by weaker-than-expected economic data from Europe and Asia. In the U.S., ongoing negotiations to avert the fiscal cliff – a series of tax increases and spending cuts scheduled to take effect at the end of the year – continued to weigh on investor sentiment.

“There’s a lot of uncertainty out there,” said one bond trader. “People are looking for a safe place to put their money, and Treasuries are still seen as one of the safest assets in the world.”

The rise in Treasury prices came despite a relatively strong auction of $35 billion in 5-year notes earlier in the day. Demand at the auction was solid, suggesting that investors remain comfortable holding U.S. government debt.

Analysts said that Treasury yields could remain low in the near term as long as uncertainty persists about the global economy and the U.S. fiscal outlook.