North Korea publicly executed two of its top officials with an anti-aircraft gun sometime in August, a report published on Tuesday by South Korea’s JoongAng Daily said. The report said that the functionaries, executed at a military academy in Pyongyang on direct orders from North Korean leader Kim Jong-un, were Hwang Min, a former agricultural minister, and Ri Yong-jin, who held a top position in the country’s education ministry.

The report said that while Hwang was arrested and sentenced to death for pushing policy proposals seen as a direct challenge to Kim’s leadership. However, the report did not detail the proposal or how it presented a challenge to the leader. Ri, meanwhile, was arrested and executed for reportedly falling asleep during a meeting held by Kim Jong-un. The education official, possibly holding a ministerial position, was also found guilty of corruption after an investigation by the country’s security ministry.

The South Korean newspaper said that Kim could have ordered the executions to retain the loyalty of his elite officials following the defection of Thae Yong-ho, the second-in-command at the North’s embassy in London. Officials from North Korea posted overseas have said to be under pressure to find new sources of cash for the country after fresh sanctions were imposed on it in March following a nuclear test in January, the report said.

Earlier, the head of the North’s army staff, General Ri Yong Gil, was executed after being found guilty of corruption and conspiracy charges.