Kim Jong-un oversaw recent 'tactical nuclear' drills, says North Korea

North Korean leader Kim Jong-un oversaw the country's tactical nuclear operation training that was held over the past few days, the state news agency reported on Monday as it released photos of Kim inspecting a missile launch at an undisclosed location in the country.

The missile that North Korea fired over Japan on October 4 was a newly developed missile aimed at delivering stronger warnings to its enemies, the report said.

Tensions are escalating in the Korean peninsula as Kim-led North Korea launched several missile tests, including one that flew over neighbouring Japan. The United States and its allies responded with bombing drills.

Pyongyang has fired several missiles in the past few weeks which has raised concerns in the region, with the US, South Korea and Japan responding with missile launches and joint military exercises this week, CNN reported

North Korea launched a suspected ballistic missile on Saturday, a day after the US and South Korea finished a naval exercise.

This was a follow-up of an unidentified ballistic missile over Japan on Tuesday. This is the first such missile launch in years, prompting a warning for residents to take cover in northern Japan.

On Saturday, South Korea's Joint Chiefs of Staff called them a "serious provocation" which harms peace and safety.

"North Korea's repeated ballistic missile launch is a serious provocation that harms peace and safety of the Korean Peninsula as well as the international community, and it is also a clear violation of the UNSC resolution," the joint chiefs said.

The joint chiefs reported that the projectiles launched had a flight range of about 350 kilometres and an altitude of about 90 kilometres.

Slamming the missile launch, US Secretary of State Antony Blinken warned if North Korea continues "down this road" of provocation it will only increase the condemnation and increase the isolation, CNN reported.

Under the Kim Jong-un regime, North Korea this year has tested a record number of missiles as it expands its weapons arsenal.