Eliza Collins

USA TODAY

Gary Johnson is confused about the civil war in Syria.

The Libertarian presidential candidate appeared on MSNBC’sMorning Joe Thursday, where he was asked what he would do about Aleppo. The city has suffered massive destruction during the Syrian civil war and is the center of the Syrian humanitarian crisis.

“And what is Aleppo?” Johnson responded.

“You’re kidding,” MSNBC’s Mike Barnicle shot back.

“No,” Johnson said.

After he was told what Aleppo was, Johnson did go on to discuss his plan for Syria — which he called “a mess" — though his plan was vague.

He recommended “joining hands with Russia to bring this civil war to an end."

Johnson said the crisis was the result of the U.S. support of a regime change.

When host Joe Scarborough questioned Johnson's lack of understanding about Aleppo, Johnson attempted to defend himself.

"You asked 'what is Aleppo?' Do you think that foreign policy is so insignificant that somebody running for president of the United States shouldn't even know what Aleppo is, where Aleppo is, why Aleppo is so important?" Scarborough asked.

"I do understand Aleppo. And I understand the crisis that is going on, but when we involve ourselves militarily, when we involve ourselves in these humanitarian issues we end up with a situation that in most cases is not better and in many cases ends up being worse," Johnson said.

#whatisaleppo was trending on Twitter shortly after the interview, as a broad swath of political commentators pilloried Johnson for being unprepared on foreign policy.

Johnson then apparently postponed and interview later Thursday morning on a New York talk radio program.

After the MSNBC interview, Johnson told Bloomberg's Mark Halperin "I am incredibly frustrated with myself."

Later Thursday, Johnson issued a lengthy statement calling the mistake a human error and promising to surround himself with the right people to avoid making mistakes if elected president.