According to Lithuanian President Gitanas Nauseda, the dismissal of Russia's Defence Minister Sergei Shoigu is intended as a signal to the Russian public.
"This is being done for the domestic market. This is being done in order to be able to continue this war. Let's have no illusions that [Russian President Vladimir] Putin is ready for peaceful negotiations," the head of state of the Baltic EU and NATO country told Lithuanian media on Sunday night in Vilnius.
"He has the feeling that he can do what he is doing. There is no other way to stop him than to support Ukraine. The most important thing is to do it quickly."
Putin dismissed Shoigu from his post and appointed him to head the Security Council of the Russian Federation, Russian state news agency TASS and the Kremlin said on Sunday evening.
More than two years after the full-scale invasion of neighbouring Ukraine, the Kremlin announced Shoigu would replace Nikolai Patrushev as secretary of the National Security Council.
Earlier TASS cited the upper house of parliament, the Federation Council, as saying that Shoigu's successor is to be the former deputy prime minister, Andrei Belousov.
No official reason was given for the change in personnel.
Putin was sworn in for a new term of office on May 7.