Russian television showed pictures of what it said were marines giving themselves up at Illich Iron and Steel Works in Mariupol on Tuesday, many of them injured.
It was not clear what plant - Azovstal or Illich Iron and Steel Works - Kadyrov meant when he talked about the 1,000 surrendered Ukrainian marines.
"Within Azovstal at the moment there are about 200 wounded who cannot receive any medical assistance," Kadyrov said in his post. "For them and all the rest it would be better to end this pointless resistance and go home to their families."
Kadyrov is an ardent supporter of Kremlin leader Vladimir Putin and has deployed many of his fighters in Ukraine to bolster Russia's drive to "demilitarise" and "denazify" Ukraine.
In earlier postings, he vowed to proceed with the capture of Mariupol and to press on to take all other Ukrainian cities, including Kyiv.
Russian television pictures showed what it said were Ukrainian soldiers being marched down a road with their hands in the air. One of the soldiers was shown holding a Ukrainian passport.
