North Korea's latest test of an intercontinental ballistic missile had outside experts warning that major U.S. cities are now within striking range. But the vice chairman of the Joint Chiefs of Staff, Gen. Paul Selva, has painted a less certain picture of the regime's capabilities.

Selva said this week it is unclear whether North Korea has the capability to target the United States, despite two successful ICBM tests, and that several key hurdles still lie ahead for it.

"It is my belief that before we assert that he, Kim Jong Un, has an intercontinental ballistic missile that can strike the United States with a nuclear weapon, he has to meet more criteria," Selva told a Mitchell Institute for Aerospace Studies group on Thursday. "First, he has to have a missile capable of ranging that distance."

North Korea launched an ICBM test on July 28 — the second in less than a month — prompting experts to estimate a 6,000-mile range and say Kim's regime now had the capability to strike major American cities.

"Based on current information, today's missile test by North Korea could easily reach the US West Coast, and a number of major US cities," wrote David Wright, physicist and co-director of the UCS Global Security Program. "It appears the ground range of the test was around 1,000 km (600 miles), which put it in or close to Japanese territorial waters. Reports also say the maximum altitude of the launch was 3,700 km (2,300 miles) with a flight time of about 47 minutes.

"If those numbers are correct, the missile flown on a standard trajectory the missile would have a range 10,400 km (6,500 miles), not taking into account the Earth's rotation," he wrote.

While Selva believes the North has ICBM range capability, he said it is far less certain that Pyongyang has the technology to send a missile on a long arc across oceans, direct it back through the atmosphere with a re-entry vehicle and strike a target with a miniaturized nuclear warhead.

"What he's saying is essentially that no, L.A. or Seattle, you are not likely to be struck by a North Korean nuclear weapon tomorrow if something goes really bad," said Hans Kristensen, the director of the Nuclear Information Project at the Federation of American Scientists.

The North has made dramatic progress on its missile program, but outside opinions might have overestimated the capabilities following the most recent test, said Kristensen, who attended Selva's talk on Thursday.

"Apparently there is a gap between what the unclassified expert community has concluded and what the intelligence community appears to be saying," he said.

While Selva's assessment might rein in some outside assumptions, the fact remains that North Korea is racing to clear the remaining hurdles of creating a viable nuclear-tipped ICBM and could soon reach its goal, Kristensen said.

"It changes the here-and-now situation, it seems to me, but it doesn't seem to change where we are going," he said. "It is happening at some point."