North Korea called the botched attempt last month to launch a military reconnaissance satellite the “most serious failure,” vowing to try a second launch without offering exact dates at the ruling party’s key meeting held from Friday to Sunday.

According to the state-run Korean Central News Agency on Monday, officials responsible for the May 31 launch were rebuked at the plenary meeting of the 8th Central Committee of the Workers’ Party of Korea, which leader Kim Jong-un chaired.

“Those officials and scientists were instructed to thoroughly learn from the failed launch and quickly prepare for a successful second launch,” the KCNA said, though it did not detail a timeline. “A task was given to lay groundwork for breakthroughs on space development and reconnaissance capability of the Korean People’s Army,” it added.

In an unusually candid admission of a rocket failure prompted by engine and fuel problems, North Korea said the day after the first launch that it would prepare for a second launch.

Pyongyang still claims it had planned to put a spy satellite into orbit to closely monitor US military activities, but the US and South Korea believe the launch was a cover for advancing missile technology, because the launch uses the same ballistic missile technology. United Nations sanctions ban the North from using such technology.

Separately, the KCNA said Kim Yong-chol, a former party official in charge of inter-Korean affairs as head of the United Front Department, was named as an alternate member of the ruling party’s politburo in a major political comeback.

A close aide to leader Kim Jong-un, Kim Yong-chol was sidelined after a 2019 Hanoi summit between North Korea and the US failed to yield any agreement. Kim had taken part in negotiations with his US counterpart, former Secretary of State Mike Pompeo.

Meanwhile, the three-day meeting discussed the economy, stressing ensuring self-sufficiency in its food supply. But leader Kim Jong-un did not deliver a speech at the meeting -- a rare moment that officials in Seoul attribute to potentially worsening economic conditions in North Korea.

“The satellite launch ended in a failure and there was not much economic progress Kim could boast. We believe those may have to do with Kim not appearing on the scene,” Koo Byoung-sam, a spokesperson for the Unification Ministry in Seoul, said at a briefing Monday. Earlier this year, the ministry said the food conditions in North Korea seemed to have worsened.