North Korean leader Kim Jong-Un, seen here in an undated picture from the North Korean official news agency, is a "rational actor" focused on the survival of his regime, a top CIA analyst says/AFP 

WASHINGTON: North Korean leader Kim Jong-Un is a rational politician and the US needs to understand that to deal with the nuclear-armed country, a top Central Intelligence Agency Korea expert said Wednesday.

"Beyond the bluster, Kim Jong-Un is a rational actor," said Yong Suk Lee, the deputy assistant director of the CIA´s Korea Mission Center.

"We have a tendency in this country to underestimate his conservatism."

"He wants to rule for a long time and die in his own bed," Lee said at a conference on the CIA at George Washington University.

US politicians including President Donald Trump have repeatedly painted Pyongyang´s strongman as irrational and "crazy."

But Lee said Kim´s focus is to stay in power, as shown by the brutal murder in Malaysia in February of his half brother Kim Jong-Nam, which has been blamed on Pyongyang agents.

"All politics is local," he said of the North Korean milieu.

The country´s long history of being surrounded by greater powers, too, means that the country is constantly on the defensive, and its leaders play that up.

"North Korea is a political organism that thrives on confrontation," Lee said.

But Kim´s fierce defense of his position and his combativeness against Washington does not mean he will act irrationally now that he has the capacity to fire a nuclear tipped missile at the United States.

"Waking up and deciding to nuke Los Angeles is not in his interest to survive," he said.