As speculation grows over the drawn-out absence of a top North Korean communist party official from public events, an American academic said Monday it might be associated with a possible setback to Pyongyang's road-mobile missile program.

"In my judgment, North Korea aborted the planned Musudan test last April because of some technical glitches discovered in its untested missile system at the pre-launch stage," said Alexandre Mansourov, a visiting scholar at the U.S.-Korea Institute at the Johns Hopkins School of Advanced International Studies.

The North was widely expected to test-launch one or two middle-range missiles from a mobile launch pad along the east coast. But it did not carry out a launch, triggering views that Pyongyang might have bowed to pressure from the U.S. or China.

Mansourov, who has followed North Korea issues for a long time, said the North Korean leader seems to have aborted the test and punished Pak To-chun, in charge of the nation's missile and nuclear programs, due to problems in preparations for the launch.

He said Pyongyang's recent charm offensive appears to be aimed at buying time to fix the technical problems uncovered in the missile development program.

"By hindsight, it was a much more prudent action on his part than to simply proceed with the half-baked test, repeating the April 2012 failure and incur international ridicule," Mansourov told Yonhap News Agency.

In what may be a similar case, he pointed out, the former economy czar, Pak Nam-ki, was purged after the botched currency reform of 2009.

If Pak To-chun returns, it would mean that problems in the Musudan missile program have been successfully resolved, said Mansourov.

Many other North Korea observers have noticed the absence of Pak, who used to attend almost all key public events, including field trips to military units.

Some say it may be related to his health or the revelation of possible personal corruption.

In June, Pak was placed on the U.S. blacklist of North Korean entities and personnel as part of measures to implement U.N. sanctions on the communist regime. (Yonhap News)