Donald Trump
POTUS is pictured in the Oval Office of the White House. Getty Images

President Donald Trump issued a tweet Sunday that designated Kim Jong-un with a new nickname, referring to him as "Rocket Man." The Rocket Man reference is a direct dig at the North Korean leader, who has conducted a series of missile launches and bomb tests to send to his enemies. Jong-un has reportedly received criticism for his actions from nearby nations and the U.N. security council.

Trump's tweets about Jong-un were a part of a tweeting spree Sunday morning. The president's tweets didn't primarily target Jong-un, but also Hillary Clinton and the New York Times. Trump's reference for the North Korean leader, however, proved to be more of a standout with social media users. The tweet followed a meeting with South Korean President Moon Jae-in, which allowed the pair to discuss a missile launched by Jong-un that overflew Japan.

"I spoke with President Moon of South Korea last night," Trump wrote in a tweet. "Asked him how Rocket Man is doing. Long gas lines forming in North Korea. Too bad!"

Trump's new nickname for Jong-un left several Twitter users puzzled. However, many users took the opportunity to criticize Trump for the mockery or poke fun at his unexpected tweet.

"This is where we're at," a user wrote in a tweet. "Rocket Man"? He's using his "Lying Ted"/"Little Marco" whiny name-calling on a global level. We've elected a child.'"

A second user tweeted, "Jesus H Christ! A US president just called the leader of a country about to blow us up "Rocket Man." Diplomacy anyone???"

"Rocket Man versus Diaper Boy," a third user wrote in a tweet. "Thank you, Mr. Putin, for hacking the vote & installing your weapon in our WH The humiliation of US is working."

Several users dismissed Trump's 'Rocket Man' comment by making reference to Elton John's hit single, "Rocket Man."

Historian Kevin M. Kruse claimed the "Tiny Dancer Mocks Rocket Man." "Sorry Trump, but Elton John is the only "Rocket Man" we acknowledge," another user tweeted. A third user added, "Has Elton John sent a cease and desist letter for the President's use of Rocket Man yet?"

The "Rocket Man" singer hasn't commented on Jong-un's new nickname at this time.

Many Twitter users echoed Comedian Jeremy McLellan's comments. McLellan tweeted, "Okay I admit I laughed out loud at Rocket Man."

Trump's tweet about Jong-un led Twitter users to primarily place their focus on the 'Rocket Man' portion. The gas lines claim, however, was overlooked by many.

Trump's "long gas lines" claim isn't completely off base. North Korea is suffering a shortage of gasoline, which has caused the country's gas stations to operate irregularly. The shortage caused sales restrictions and a hike in gasoline prices, according to a USA Today report in April. At least one North Korean gas station in Pyongyang, the nation's capital, charged more than $5 a gallon.

The nation's gas prices reportedly climbed to $6.25 per gallon in June. North Korea's inflated gas prices make it one of the most expensive country's to obtain gasoline from, but it still doesn't crack the top 10. Hong Kong reportedly has the highest gasoline prices at $8.62 per gallon, with Iceland and Norway following shortly behind.