North Korea has attempted to launch its first military spy satellite - sparking emergency alerts in neighbouring South Korea and in Japan.
Air raid sirens sounded off across South Korea's capital Seoul on Wednesday morning, while Japan also issued a missile warning following the launch of a rocket from North Korea's northwestern Tongchang-ri area.
It comes after Pyongyang announced plans to launch its first military spy satellite - which it said would be used to monitor US activity.
The country's state-controlled news agency KCNA reported on Wednesday that the launch of the satellite had failed and that the rocket had crashed into the Yellow Sea.
It said officials would investigate the "grave" defects - believed to have involved the rocket's engine and fuel system - and that a second launch would take place soon.
On Wednesday, the US condemned the launch attempt - which it said involved the use of ballistic missile technology - and that Joe Biden and his security team were assessing the situation in coordination with allies.
South Korea's military described Wednesday's rocket by its neighbour as a "space-launch vehicle".
It also said that it had recorded an "abnormal flight" before the rocket plunged into the sea.
Officials in South Korea's capital of Seoul sent alerts over public speakers and smartphones for residents to prepare for evacuation following the launch.
However, there were no immediate reports of damages or disruption.
The Japanese government also issued an emergency warning over its J-Alert broadcasting system for its Okinawa region following the rocket's launch. Authorities later lifted the alert.
However, Japan's defence minister, Yasukazu Hamada, said the country would keep its missile defence system on alert as a result of the launch attempt.
It comes after Japan's coast guard said on Monday that it had been informed by North Korea of a plan to launch a satellite between 31 May and 11 June.
A satellite launch by North Korea is a violation of UN Security Council resolutions that ban the country from using ballistic technology because it is regarded as a cover for missile tests.
Earlier this month, North Korean leader Kim Jong Un and his daughter were pictured examining the country's first military spy satellite.
During his visit, Kim approved an unspecified "future action plan" in preparations for launching the satellite, North Korea's official Korean Central News Agency (KCNA) said.
Wednesday's flight was North Korea's sixth satellite launch attempt, and the first since 2016.