The former chief of the North Korean military's general staff had said in 2012 that the North is capable of hitting the United States with a nuclear weapon atop a long-range missile, a report showed Thursday.

Ri Yong-ho, who was purged in July 2012, said earlier that launching a satellite amounts to firing a rocket, effectively acknowledging that the North's rocket launch is a covert test of an intercontinental ballistic missile, according to South Korea's state-run broadcaster KBS.

"If we put a nuclear warhead atop a rocket, it can fly to the U.S. That's why we are confident," Ri was quoted as saying during a lecture for North Korean senior officials in early 2012.

"We have nuclear weapons. The U.S. claims that we are not a nuclear-armed nation," he said. "Whether the U.S. recognizes it or not, we are a nuclear state."

His remarks were only recorded as an audio file, but many experts on North Korea said that it was Ri's voice.

North Korea has notified U.N. agencies that it will launch what it calls an "earth observation satellite" sometime between Feb. 8 and 25.

North Korea has claimed it has the sovereign right to launch "a series of satellites for peaceful purposes." But Seoul and Washington view the North's move as cover for ballistic missile tests.

"The North's claim that it has the right to develop outer space for peaceful purposes cannot be justifiable, (given Ri's remarks)," said Kim Yong-hyun, a professor of North Korean studies at Dongguk University. "Considering Ri's status was firm right before being purged, his comments should not be dealt with lightly."

Ri was once known as one of the closest confidants of North Korean leader Kim Jong-un, but in 2012 he was removed from all his posts because of an unspecified "illness." (Yonhap)