WATCH: US presidential candidate mocked over Aleppo gaffe

This was not how US presidential candidate Gary Johnson hoped to finally crack the headlines: mocked mercilessly on Twitter for asking an interviewer "What is Aleppo?" in response to a question about the war-ravaged Syrian city.

But the exchange on Thursday morning instantly thrust the former New Mexico governor, who is standing as a Libertarian in November's vote, into a global spotlight, with #ThisIsAleppo quickly becoming a trending hashtag.

On Twitter, the verdict was instant and clear, with a deluge of posts ranging from sarcasm to disbelief.

"You hear that? That's the sound of Gary Johnson's campaign coming to a crashing halt," one user posted.

But many on social media also voiced dismay, posting poignant pictures of years of bloodshed in the Syrian city under the phrase "This is Aleppo."