The Bank of Japan kept its aggressive monetary stimulus policy unchanged after a two-day meeting through Wednesday, opting instead to monitor the effectiveness of recent tweaks amid chronically weak inflation.

BOJ Gov. Haruhiko Kuroda told a news conference that "the current powerful monetary easing measures are still necessary to achieve our 2 percent price stability target."

The central bank's decision-making board voted 7-2 to maintain ultralow interest rates while pledging to keep rates down "for an extended period of time." It also kept unchanged its hefty purchases of risky assets including exchange-traded funds.