SEOUL, April 2 (UPI) — Incoming U.S. National Security Advisor John Bolton has expressed “very healthy skepticism” of North Korea’s move toward dialogue on denuclearization, according to Republican senator Lindsey Graham.

Graham told Fox News Sunday that Bolton had recently expressed fear that Pyongyang was “just buying time” to develop its nuclear weapons while pushing for talks with Donald Trump.

“They are about nine months to a year away from having a missile with a nuclear weapon on time that can hit America,” the senator said. “He sees these negotiations as a way of buying time, that’s what they’ve done in the past.”

Bolton, a Bush-era ambassador to the United Nations, has been an advocate of launching military strikes on North Korea to prevent its development of nuclear weapons that could hit the U.S. mainland.

Graham also expressed doubt regarding the terms and conditions of the upcoming summit but said the negotiations should be “very focused and get quick action” to ensure the North gives up its nukes.

“We don’t want to give them nine months to talk and build a missile at the same time,” he said.

The remarks came after U.S. media reports last week suggested the reclusive state has started testing an experimental light water nuclear reactor and brought another nuclear reactor online, ahead of its summit with Washington.

Both reactors could be used to produce fissile materials needed for nuclear bombs, according to the Washington Post.

Subsequent satellite imagery analyzed by North Korea monitoring website 38th North on Friday indicates the North has built new facilities near the ELWR in its Yongbyon test facility, which the website says is likely to be staffed by personnel associated with future ELWR operations.