John McCain
John McCainReuters

Senator John McCain (R-AZ) said on Sunday that the Trump administration should consider a pre-emptive strike against North Korea if the U.S. determines that country's regime can mount a nuclear weapon onto a ballistic missile.

At the same time, he cautioned military action should be the last resort.

"I think that we have to consider that option as the very last option, and for a number of reasons," McCain was quoted as having told CNN. He added that ruling out possible military action was "foolish."

One of the reasons for caution, he continued, is the close proximity of South Korea's capital, Seoul, to North Korea. Should a shooting war break out, McCain said, "The carnage would be horrendous."

President Donald Trump, in an interview with CBS on Saturday, would not rule out the use of military force against North Korea, answering, "I don't know. I mean, we'll see” when asked about such a move.

McCain on Sunday called on China to use its leverage over North Korea to "put the brakes on this."

"This is very serious. Their capabilities of firing artillery on Seoul is absolutely real," he warned. "And this, again, is why we have to bring every pressure to bear. And the major lever on North Korea today, and maybe the only lever, is China."

The comments mark the second time this week that McCain has criticized China. Late last week he said China had done nothing to stop North Korea's provocations.

“Frankly, over the years we’ve seen nothing from China,” he said on MSNBC. “They’ve propped up North Korea. They could shut down their economy in a week or two if they wanted to.”

Last month, McCain referred to North Korean leader Kim Jong-Un as a “crazy fat kid”, adding that “China is the one, the only one, that can control” him.