SINGAPORE, April 25 (Reuters) - Japanese government bond yields were hemmed into narrow ranges on Monday by the Bank of Japan's bond buying operation, alongside a respite in the selloff in the yen and in U.S. Treasuries.

Benchmark 10-year JGB futures rose 0.18 point to 149.27, while the 10-year JGB yield was flat at 0.245%, just off the top of the Bank of Japan's policy band.

Two-year JGB yields were also steady at a negative 0.055%.

As part of efforts to defend its yield curve control policy, the BOJ began consecutive purchases of 10-year JGBs at a fixed rate of 0.25% for four business days from Thursday.

That offer came as the yen hit two-decade lows and bets grew that the BOJ will have to adjust monetary settings at its policy meeting this week and as the yield on the 10-year JGB hit 0.25%, the upper limit of its target of around zero percent.

Among major currencies, the Japanese yen has been the most affected by rising U.S. interest rates, with Japan keeping its benchmark yields pinned down. The dollar was marginally firmer on the yen on Monday, in a range between 128.24 and 128.87.

The dollar has gained 11% on the yen so far this year. Last week's 129.43 was the highest for dollar-yen in 20 years. (Reporting by Vidya Ranganathan; Editing by Vinay Dwivedi)