South Korea's military says it has detected many pieces of debris following the announcement of North Korea's launch on Monday night of what it claimed was a reconnaissance satellite.

The South Korean military's Joint Chiefs of Staff announced that the projectile was fired from Tongchang-ri in North Korea's northwest toward the Yellow Sea.

Officials say many pieces of debris were detected in waters two minutes after the launch. The US and South Korea are reportedly analyzing the debris.

South Korea's Yonhap News Agency reported that the launch appears to have failed, given the discovery of debris immediately thereafter.

Yonhap earlier quoted South Korean government officials as saying Russian engineers came to North Korea to help its satellite launch program by conducting engine combustion tests.

North Korean leader Kim Jong Un has said the country would launch three reconnaissance satellites this year.