Ukrainian President Volodymyr Zelensky on Saturday issued a decree sacking a senior security figure and said separately that his drive to clean up the government would continue.
Authorities have dismissed dozens of officials in recent weeks and opened probes as part of a widespread drive against wrongdoing. The European Union says addressing corruption is a requirement for Ukraine joining the 27-member bloc.
Zelensky dismissed Ruslan Dziuba as deputy commander of the National Guard, according to a brief decree issued by the presidential office. It did not give any reasons for the move.
Zelensky - who has stressed the need for the defence ministry in particular to be cleaned up - did not specifically mention Dziuba in his daily video address.
Instead, he said he had met defence sector and law enforcement officials to discuss ways to protect institutions from what he called attempts from outside or inside to reduce their effectiveness and efficiency.
Referring to the crackdown, he said: "All this activity is not just about certain episodes or criminal proceedings ... the state will continue to modernise the institutions themselves. The purity of the work of state structures must be guaranteed."
Ukraine's defence minister said on Thursday hundreds of officials at the ministry or in the armed forces had been disciplined last year after internal audits, and that he had "zero tolerance" for corruption.
