Kim Jong-un oversaw the test-firing into the sea of Japan, which was part of an effort to assess the "accuracy and reliability" of a new autonomous navigation system, according to the KCNA.

The North Korean leader was quoted as saying he was "very satisfied" with the test.

On the same day, Kim visited a munitions factory and called for the country's "nuclear force to be further strengthened at the fastest possible speed ... without any pause or hesitation," the state news agency reported.

"The enemies would be terrified and dare not provoke us if they witness the actual combat nuclear force of our state," Kim said.

South Korea's Joint Chiefs of Staff said on Friday that North Korea had fired a ballistic missile off the country's east coast.

The launch was the latest in a series of weapons tests carried out by North Korea in recent months.

Analysts say North Korea may believe that an expanded arsenal will give Pyongyang more leverage in future talks with Washington, the Associated Press news agency reports.

On Friday, North Korea also denied that it had exported weapons to Russia, calling speculation about arms transfers between Pyongyang and Moscow "the most absurd paradox", according to state media.

"We have never exported weapons and ammunition to Russia nor have we any plan to do so in the future," Kim Yo-jong, the influential sister of the North Korean leader, said in a statement carried by the official KCNA news agency.

Several countries, including the US and South Korea, have accused North Korea of supplying artillery shells, missiles and other weapons to Russia for use in the war in Ukraine, in exchange for advanced military technology and economic aid. Both North Korea and Russia have repeatedly denied the allegations.

Foreign experts believe that North Korea's recent flurry of short-range missile and artillery tests are likely intended to test or promote weapons systems that it hopes to sell to Russia.

Kim Yo-jong, who is a member of North Korea's powerful National Defence Commission, also said that North Korea's recent weapons tests were conducted as part of the country's five-year plan for weapons development that was unveiled in 2021.

She added that the newly tested weapons were designed to strike the South Korean capital.

"We do not hide that such weapons will be used to deter any military action by South Korea," she said.

The deepening ties between North Korea and Russia come as both countries are locked in separate confrontations with the United States - North Korea over its advancing nuclear programme and Russia over its invasion of Ukraine.

Read more: North Korea fires suspected ballistic missile into sea