Investigations of the Putin forces' use of weapons that kill across a substantial area: cluster bombs, powerful bombs, fléchettes and unguided missiles.

The treaty that entirely prohibits cluster bombs has not been signed by the world's main military powers, or by Ukraine. So I think it is a mistake to suppose that use of cluster bombs is, ipso facto, a war crime.

However, the more general treaty against using imprecise weapons in residential areas must cover cluster bombs along with the other weapons described in the article. So the use of cluster bombs there would be war crimes.