The containment building covering the exploded nuclear rector number 4 at Chernobyl has been hit by missile attack on Friday. The video below shows the missile hitting the containment building with visual confirmation of the damage available later in the video.
The New Safe Confinement (NSC or New Shelter) is a structure put in place in 2016 to confine the remains of the number 4 reactor unit at the Chernobyl Nuclear Power Plant, in Ukraine, which was destroyed during the Chernobyl disaster in 1986.

The structure also encloses the temporary Shelter Structure (sarcophagus) that was built around the reactor immediately after the disaster. The New Safe Confinement is designed to prevent the release of radioactive contaminants, protect the reactor from external influence, facilitate the disassembly and decommissioning of the reactor, and prevent water intrusion.
Do we know if there are russian troops still in the area or have they left?
This is a very serious development in the conflict.
Who would be stupid enough to do this and risk radiation and contamination to be released into the area once again?