The Fed is expected to announce a new round of Treasury securities purchases after its two-day meeting. Half the respondents in a Reuters poll on Friday said they expected $45 billion per month.

Yields on 10-year Treasuries inched down to 1.650 percent on Wednesday in Asian trade, compared to 1.652 percent in late US trade on Tuesday.

Yields on 30-year Treasuries also fell slightly to 2.836 percent from 2.838 percent on Tuesday.

"Expectations of more Fed easing as well as the continuation of talks on the 'fiscal cliff' budget situation make it difficult to sell US debt," said a fixed-income fund manager at a Japanese asset management firm.

The White House and US House of Representatives Speaker John Boehner exchanged new proposals in the talks to avert the $600 billion worth of tax increases and reduced outlays scheduled to automatically take effect next year.

A group of high-profile chief executives urged President Barack Obama and Republican congressional leaders on Tuesday to reach a deal to end the stalemate.

Strategists at Societe Generale recommended keeping long positions in US Treasuries ahead of the Fed outcome.

If there is no substantial progress towards resolution of the fiscal cliff prior to the Fed' policy announcement, the 10-year yield is likely to break out of the 1.58 percent to 1.75 percent range on the downside, they said in a note to clients. It could fall back towards 1.50 percent in the coming days if the fiscal cliff negotiations bog down, they added.

On the supply side, the Treasury will sell $21 billion in 10-year notes on Wednesday and $13 billion in 30-year bonds on Thursday.

On Tuesday, it sold $32 billion of three-year notes at a high yield of 0.327 percent, with a below-average bid-to-cover ratio of 3.36.

Center>Copyright Reuters, 2012