The Bank of Japan said on Thursday it would conduct emergency bond buying operations as yields on Japanese government bonds hit multi-year highs ahead of the bank’s policy meeting next week.

The benchmark 10-year government bond yields touched 0.255% above the bank’s top end of the policy band for a second day, as investors tested the BOJ’s commitment to defend its ultra-low rate policy.

The yield on the 20-year bond rose to its highest since September 2015.

The BOJ remains an outlier among a global wave of central banks tightening monetary policy to combat soaring inflation, as it focuses on underpinning a fragile economy.

Yields kept rising even as the central bank last month boosted the amounts of regular bond buying for the current quarter.

On Thursday, the BOJ offered to buy 100 billion yen ($666.98 million) of JGBs with maturities of 10-20 years, and another 100 billion of bonds with maturities of five-10 years.

Reuters