North Korea launched short-range missiles off its western coast Thursday, South Korea's Defense Ministry said, but it was still unclear how many had been fired.

"We have intelligence that North Korea fired short-range missiles into the waters off its western coast, and we are trying to confirm how many were fired and what type of missiles they are," a Defense Ministry official said on customary condition of anonymity.

The news came two weeks after North Korea test-fired at least one short-range missile into eastern coastal waters, which South Korean and U.S. officials played down as part of the communist country's regular military drills.

Thursday's missile launches come as North Korea is refusing to move on its pledge to shut down its main nuclear reactor over a delay in withdrawing of $25 million at a Macau bank, which was blacklisted by the U.S.

The North has made the funds' release a key condition to disarmament, having boycotted international negotiations for more than a year over the issue, during which it conducted a nuclear test last October.

Last July, North Korea also fired a barrage of missiles, including a long-range one believed to be capable of reaching even parts of the United States.