The Bank of Japan injected 2 trillion yen into the market Wednesday to keep the banking system stabilized following terrorist attacks in the United States.

"The Bank of Japan will do all it can do to help smooth fund settlements and ensure stability in the financial system, including providing an ample amount of liquidity," BOJ Gov. Masaru Hayami said in a statement.

The 2 trillion yen was supplied into the market through two rounds of bill-buying operations.