Moscow, Russia - Russian President Vladimir Putin has dismissed his defense minister, Sergei Shoigu, in a major shake-up amid Moscow's war on Ukraine.

More than two years after Russia's full-scale invasion of its neighbor, Shoigu move into a new role, replacing Nikolai Patrushev as secretary of the National Security Council, the Kremlin announced.

Earlier, state news agency TASS cited the upper house of parliament, the Federation Council, as saying that Shoigu's successor is set to be the former deputy prime minister, Andrei Belousov.

Putin was sworn in for a new term of office just a few days ago.

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"Today, the winner on the battlefield is the one who is more open to innovation and its implementation," Kremlin spokesperson Dmitry Peskov said, explaining the decision to appoint a civilian to head the Ministry of Defense.

Belousov is not only a civil servant but has also worked successfully in politics for many years and advised Putin on economic issues.

He is "undoubtedly the best candidate" to expand the Russian defense industry complex and introduce new technologies, Sergei Gavrilov, a lawmaker in the lower house, or Duma, was quoted as saying by TASS.

There had been some speculation about the possible dismissal of 68-year-old Shoigu, who had been defense minister since 2012.

A few weeks ago, one of Shoigu's deputies, Timur Ivanov, was arrested on corruption charges. Observers had interpreted this as a sign of power struggles within the Russian military and security apparatus.

Chief of the General Staff Valery Gerasimov will remain in his position, Peskov stressed. The military component in the Ministry of Defense will remain unchanged even after the appointment of Belousov, he added.

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Shoigu's 65-year-old successor Belousov was Putin's adviser on economic issues for many years and has held various posts in the government in recent years.

Among others, he was acting prime minister for several weeks in 2020 when Mikhail Mishustin was unable to work due to a coronavirus infection.

After 20 years in office, Sergei Lavrov will remain Russia's foreign minister in accordance with Putin's wishes as submitted to the upper house, the Federation Council announced on Telegram on Sunday evening.

The 74-year-old has been in office since 2004, making him one of the longest-serving foreign ministers in the world. Putin's close ally is considered indispensable in times of crisis.

Russia has been making battleground gains in Ukraine, with thousands of residents evacuated from the Kharkiv region in the east amid a strong push by the invading forces.