The nuclear-armed country stages military parades to mark important holidays and events that feature thousands of goose-stepping troops followed by a cavalcade of armoured vehicles and tanks and culminating with the key missiles Pyongyang wants to display.

Observers closely monitor these events for clues on North Korea's latest weapons development.

Monday's parade to celebrate the 90th anniversary of the founding of the Korean People's Revolutionary Army began at around 10 pm local time (1300 GMT) at the Kim Il Sung Square in Pyongyang, the source said.

It was widely expected to showcase the North's most sophisticated weaponry including the "monster" Hwasong-17 ICBM as well as hypersonic and submarine-launched ballistic missiles.

North Korea has held three nighttime military parades in recent years, with state media only reporting on the events the next day. As of Monday night, state media had not reported on the latest parade.

But specialist service NK News said at least a dozen "illuminated objects" were spotted over central Pyongyang late on Monday night in a possible indicator of a military parade or practice.

Pyongyang has carried out more than a dozen weapons tests this year, including firing an intercontinental ballistic missile at full range for the first time since 2017.

US and South Korean officials and analysts have also warned Pyongyang could resume nuclear weapons testing for the first time since 2017, citing renewed activity at its key testing site.