North Korean leader Kim Jong-un has supervised the test-firing of a new type of "tactical guided weapon," the country's state media has reported.

It said the "advantages" of the weapon were "the peculiar mode of guiding flight and the load of a powerful warhead".

The KCNA report did not provide further details about the weapon, but said Mr Kim described its development as one "of very weighty significance in increasing the combat power of the People's Army".

KCNA added that the test was "conducted in various modes of firing at different targets" and that Mr Kim "guided the test-fire".

The announcement came the day after a US monitor, the Center for Strategic and International Studies, said activity had been detected at North Korea's main nuclear site.

It suggested Pyongyang may be reprocessing radioactive material into bomb fuel since the collapse of a February summit with Washington.

That meeting, the second between US President Donald Trump and Mr Kim, ended abruptly without agreement on Pyongyang's nuclear programme.

Since then, North Korea has said it is mulling options for its diplomacy with the US, while Mr Kim said last week he was open to talks with President Trump only if Washington came with the "proper attitude".

"Kim is trying to make a statement to the Trump administration that his military potential is growing by the day," said Center for the National Interest analyst Harry Kazianis.

"His regime is becoming frustrated with Washington's lack of flexibility in recent negotiations."

Last November, KCNA reported that Mr Kim oversaw the testing of a "newly developed ultramodern tactical weapon" months after his first meeting with President Trump.

It was the first official report of a weapons test by North Korea since it began negotiations with Washington over its nuclear and missile programme.