President Vladimir Putin visited Mariupol, a Ukrainian territory now in Russian hands.
The website of the State Duma, parliament’s lower house, said the move would enable the military to utilise the skills of older professionals.
Ukraine’s deputy defence minister Hanna Malyar says over 260 Ukrainian soldiers have been evacuated from the Azovstal plant in the embattled city of Mariupol.
British military intelligence said on Friday that Russian forces were continuing their ground assault on the Azovstal steel plant for a second day.
UN Secretary-General António Guterres called on the Russian leadership to end the war in Ukraine and to allow the UN to help evacuate people.
Mr Shoigu announced this on Thursday at a meeting with President Vladimir Putin broadcast on state television.
“We have provisionally succeeded in agreeing on a humanitarian corridor for women, children and the elderly.”
Russia’s Foreign Minister Sergey Lavrov says the next phase of invasion “will be a very important moment of this entire special operation”.
Top Ukrainian official rejected Russian claims that it had taken control of the port in Mariupol, and over 1,000 Ukrainian troops surrendered.
The Russian military claimed that it launched strikes on 32 military targets in Ukraine during the night.
