Russian President Vladimir Putin has already recruited up to 35,000 prisoners including rapists, murderers and even a 'maniac' cannibal to fight in his war in Ukraine. 

The new recruits will be pardoned and will be free to live in society no matter how heinous their crimes if they survive six months of war. 

This week, Wagner chief Vevgeny Progozhin visited the former Gulag prisoner camp territory of eastern Siberia and the Russian Far East to sign up yet more convicts. 

It is suspected thousands of these prisoners have already died in battle as they have been used as cannon fodder to slow Ukraine's fightback.  

As many as 40 of the prisoners have been executed for desertion or treason by the Wagner private army,' Olga Romanova, from human rights group Russia Behind Bars told Mozhem Obyasnit media outlet. 

Speaking about the new recruits, who have been plucked from prisons across Russia, Romanova said: 'We have started to hear that he has begun taking rapists, too. 

'They have also taken a maniac from [a jail in] Saratov region, who has cannibalism in his 'portfolio'.' 

Romanova put the latest figure of inmates freed to fight at between 30,000 and 35,000, with another source saying the number of murderers 'runs into hundreds'. 

The higher figure is almost one-third the size of the British army. 

Those who survive six months will have their remaining sentences wiped.  

But at least 40 had been killed in extrajudicial killings, said Romanova. 

They are executed for desertion, surrendering, looting, alcohol or drug abuse, and for sexual intercourse, she said. 

Such killings are illegal but will now be hidden as state secrets, she said. 

The recruitment of inmates from high security jails began in June and with Priogozhin's trip to Primorsky region, it now stretches from the Baltic to the Pacific. It covers some 30 oblasts or regions. 

Last night a report came about him visiting Spassk-Dalny, around 6,000 miles east of Moscow. 

Some 200 inmates wrote statements seeking to go and fight. 

Earlier Priogozhin had been in Yakutia, a region notorious for old Stalin-era GULAG camps, the Daily Mail reported.