WASHINGTON, April 22 (UPI) -- A State Department spokesman said during an interview Friday that Donald Trump is "not the only" presidential candidate who has world leaders nervous.

State Department spokesman John Kirby did not mention any other candidates by name, but appeared to be invoking Texas Sen. Ted Cruz, who has said he would "make the sand glow" in the Middle East -- a reference to using nuclear weapons there.


The Republican presidential race has drawn headlines for what many consider the harsh isolationist tone set by front-runner Trump, who has advocated for revisiting the cornerstone military alliance the North Atlantic Treaty Organization, or NATO. Trump has also said he would consider backing away from obligations the United States has made to protect Asian allies Japan and South Korea if they are not willing to pay more for U.S. help. He also suggested he would require those countries to build their own nuclear stockpiles, rather than rely on the U.S. nuclear umbrella against potential threats from Russia, China or North Korea.

"There are scant few foreign leaders that [Secretary of State John Kerry] meets with where the issue doesn't come up in terms of the rhetoric in the campaign. Now, it's not always centered on one or another candidate, to be honest with you," Kirby said on MSNBC's Morning Joe.

Kirby said Kerry has heard "some real concern about the rhetoric, the isolationist sentiments that some are expressing, and almost xenophobic ideas out there."