The launch effort came on the birthday of Kim Il Sung, the founder of North Korea, on the holiday known as "Day of the Sun."
"If the reports are true, and this mobile missile launch attempt did fail, it would be a major disappointment for the North Korean regime because it is happening on the most significant holiday of the year," said CNN's Will Ripley from Pyongyang.
No official announcement had been made about the test within the country, Ripley said. Based on past failures, it was unlikely one would ever be made.
"Most North Koreans will never know that it happened," he said.
No official word of apparent failed missile launch here in #Pyongyang. If true, big disappointment for #NorthKorea on Day of the Sun holiday
A U.S. defense official said a North Korean missile launch had failed at 4:33 p.m. ET Thursday, after the U.S. Strategic Command systems detected and tracked the attempt. At this time, there was "no evidence the missile reached flight," a U.S. official told CNN's Barbara Starr.
A U.S. State Department official said after the launch failure: "We have seen the reports. We are closely monitoring the situation."
"We call again on North Korea to refrain from actions and rhetoric that further raise tensions in the region and focus instead on taking concrete steps toward fulfilling its international commitments and obligations."
The images are said to show small vehicles, a support building and portal.
Eventful year for North Korea
Tensions have ratcheted up on the divided Korean peninsula this year as Pyongyang has made a series of assertions about developments in its military capability.
15 photos:North Korea's verbal volleys
Pyongyang carried out its fourth nuclear test in January. It said it succeeded in miniaturizing nuclear warheads to fit on medium-range ballistic missiles -- which U.S. intelligence analysts say is probably true.
In response, the U.N. Security Council -- with the support of China -- imposed broad sanctions against North Korea in March. But the sanctions and international pressure have not held any sway in North Korea's aggressive efforts to build up its weapons and nuclear capabilities. The country maintains that it's developing weapons to defend itself from the United States.
The Unification Ministry in South Korea suspected that Kim Jong Un, the North Korean leader, ordered the latest missile test.
"By showing its strong will that it will continue to do so despite the current sanction against the country, it appears to be attempting to split opinions in the international community as well as building up achievements for Kim Jong Un ahead of the Party's Congress," said Jeong Joon-hee, the spokesman for the ministry.
North Korea plans to convene its seventh Communist Party Congress in May this year -- which is rare and potentially significant. The last congress of the Workers' Party of Korea was held in 1980 and that culminated in the announcement that Kim Jong Il, the father of the current leader, would take power.