North Korea has launched an unidentified ballistic missile towards waters off its eastern coast, South Korea’s military said.

South Korea’s Joint Chiefs of Staff said in a short statement the launch towards the East Sea, which is also known as the Sea of Japan, occurred on Thursday morning but gave no further details.

North Korea has not test-launched a missile since September 18 when it last fired multiple short-range ballistic missiles, South Korea’s Yonhap news agency reports.

The reported missile launch comes a day after South Korea’s military intelligence agency told lawmakers that North Korea has likely completed preparations for its seventh nuclear test and was close to test-firing a long-range missile capable of reaching the United States.

The launch also comes amid concerns about North Korea’s reported troop dispatch to Russia to support its war against Ukraine.

Speaking at a news conference in Washington with South Korean Defence Minister Kim Yong-hyun on Wednesday, US Defense Secretary Lloyd Austin said North Korean troops wearing Russian uniforms and carrying Russian equipment are moving towards Ukraine, in what he called a dangerous and destabilising development.

South Korea reports that North Korea has sent more than 11,000 troops to Russia and that more than 3,000 of them have been moved close to fighting in Western Russia.