It said this launch could be part of a series of military provocations by the reclusive state to show defiance as the three leaders of international pressure on Pyongyang and its weapons programs confer Friday outside Washington.

The show of force could also be designed to protest US-South Korean military exercises which start Monday and are due to last the rest of the month, the agency said.

Yonhap quoted a lawmaker, Yoo Sang-bum, who sat in on a briefing of the parliamentary intelligence committee by the National Intelligence Service.

"We are continuously identifying signs of preparation for an ICBM launch, such as the frequent movements of propellants out of liquid fuel factories," Yoo said, according to Yonhap.

Yoo also said the North is expected to conduct a joint exercise of its armed forces, including the test launch of a missile that can be fitted with a tactical nuclear weapon.

His remarks came as US President Joe Biden prepared to welcome South Korean leader Yoon Suk Yeol and Japanese Prime Minister Fumio Kishida to the president's retreat at Camp David on Friday. The unprecedented three-way summit is designed to show a message of strength to China.

Pyongyang has sped up its testing of nuclear-capable missiles in the past year, heightening tensions across East Asia.