"The armed forces of Belarus continue joint training with the fighters of the Wagner PMC (Private Military Company)," the Belarusian defense ministry said.
Despite his state of undress, Prigozhin has developed a reputation as a fashionista.
An adviser to Belarus' defence ministry said on Friday that nobody from the Wagner group had yet visited the disused military camp that Lukashenko had offered for the fighters' use.
"You know where you are situated geographically, and you know pretty well where the threat is coming from", said Lt Col Steffen Lieb, commander of the Patriot deployment.
Belarusian President Lukashenko stated he has a veto on use of Russian tactical nuclear weapons deployed on Belarusian territory.
Alexander Lukashenko, who has ruled Belarus since 1994, dismissed claims that he was "Europe's last dictator" on Thursday.
Yevgeny Prigozhin, the leader of the Wagner mercenary group, is no longer in Belarus and there are reports that he may have returned to Russia.
China’s President Xi Jinping and Russian leader Vladimir Putin will participate in the virtual summit, which will be Putin’s first appearance at an international event.
Polish Prime Minister Morawiecki stated that Poland wants to join NATO's nuclear weapons sharing program, in response to Russia's deployment of nuclear warheads to Belarus.
The Belarusian president, in an address marking his ex-Soviet state's national day, said the stationing of the weapons in Belarus was "my firmest initiative".