Seoul, Jun 26 (IANS): North Korea launched a ballistic missile toward the East Sea on Wednesday, but the missile exploded in the air, South Korea's military said, amid a possibility that the North could have test-fired a hypersonic missile.

The Joint Chiefs of Staff (JCS) said the missile was launched from an area in or around Pyongyang at around 5:30 a.m. local time, and the intelligence authorities of South Korea and the United States are conducting a detailed analysis.

A military source told Yonhap news agency that the North appears to have test-fired a hypersonic missile, but the test is believed to have ended in failure after the missile flew some 250 kilometres.

A JCS official later told reporters on condition of anonymity that the military is considering the possibility of a hypersonic missile launch, noting that the missile exploded in mid-air over waters off the North's east coast.

Smoke appeared to emanate from the missile more than previous launches, the official said, raising the possibility of combustion issues. The official added the missile could possibly be powered by solid propellants.

Solid-fuel missiles are considered to be harder to detect ahead of a launch compared with liquid-fuel ones as they require less preparation procedures, such as the injection of fuel.

The launch came after the North slammed the arrival in South Korea of the US aircraft carrier USS Theodore Roosevelt and warned of taking "overwhelming and new" deterrence measures against what it called a "provocative" act.

The aircraft carrier arrived in Busan, 320 kilometres southeast of Seoul, on Saturday ahead of a trilateral exercise with South Korea and Japan.

President Yoon Suk Yeol boarded the aircraft carrier Tuesday, saying the visit symbolised the "firm" US security commitment to South Korea and that trilateral cooperation among South Korea, the US and Japan will become another "powerful" deterrent.

The missile launch also came after the North signed a comprehensive strategic cooperation treaty with Russia during a summit last week between Russian President Vladimir Putin and North Korean leader Kim Jong-un, which includes a pledge for the two countries to come to each other's aid if attacked.

Hypersonic missiles are on the list of sophisticated weapons North Korean leader Kim Jong-un vowed to develop during a key party congress in 2021.

Such missiles travel at a speed of at least Mach 5 -- five times the speed of sound -- and are designed to be manoeuvrable on unpredictable flight paths and fly at low altitudes.

In April, the North claimed to have successfully test-fired a new intermediate-range ballistic missile tipped with a hypersonic warhead.

Wednesday's launch also took place hours after the North sent trash-carrying balloons to the South on Tuesday night for the second straight day.

Since late last month, North Korea is estimated to have launched more than 2,000 such balloons in a "tit-for-tat" move against anti-Pyongyang propaganda leaflets sent by North Korean defectors and activists in the South.

The North last launched multiple short-range ballistic missiles into the East Sea on May 30.