Ukrainian army chief Valeriy Zaluzhnyi has called for a "completely new state system of technological rearmament" in an opinion piece published after several media outlets reported that he could be dismissed from his post.
General Zaluzhnyi made no mention of a rift with President Volodymyr Zelenskiy or the possibility of him leaving his post in the piece published by CNN.
The US outlet said he wrote the piece before "an expected announcement of his dismissal".
CNN cited a source earlier saying that Zelenskiy was set to announce Zaluzhnyi's dismissal within a matter of days in what would represent the biggest shake-up of Ukraine's military during Russia's full-scale invasion.
Zaluzhnyi said in the article that Ukraine needed to find new ways and capabilities to gain an advantage over Russia as the full-scale war nears its third year.
"The challenge for our armed forces cannot be underestimated. It is to create a completely new state system of technological rearmament," he wrote.
"Taking everything into account at this moment, we think the creation of such a system could be achieved in five months. Our partners are of the same view."
Meanwhile, Russian investigators said on Thursday they had evidence showing that Ukraine's military shot down a Russian Il-76 military transport plane last week with US-made Patriot surface-to-air missiles.
The Russian Air Force Il-76 fell from the skies on January 24.
Russia said all 74 people on board, including 65 captured Ukrainian soldiers en route to be swapped for Russian prisoners of war, were killed, and blamed Ukraine for downing the plane.
The investigators released footage of body parts which they said proved those aboard were Ukrainian military personnel.
Ukraine has neither confirmed nor denied that it downed the plane but has challenged details of Russian authorities' account and called for an international investigation.
Russia's State Investigative Committee said in a statement that Ukrainian soldiers in the area of Lyptsi in the Kharkiv region had fired two missiles at the plane.
Among the fragments were serial numbers with English acronyms, including "CONFIDENTIAL classified by PATRIOT SECURITY CLASSIFICATION GUIDE DATED: 9/22/83 ADDENDUM DATED 11/28/83 8/8/84 CONTRACT NO/DAAH01-86C-A018'," the committee said in a statement.
"The fragments seized from the scene, according to their design features, geometric characteristics and available markings, are structural elements of the MIM-104A anti-aircraft guided missile of the Patriot complex of the United States, developed by Raytheon and Hughes corporations and manufactured by Raytheon," the committee said.
It published a short video showing investigators inspecting some of the 116 missile fragments on the ground in an unspecified location.
One of the fragments included the what appears to be "ATRIOT" in English.
A separate video from the Investigations Committee, which appeared to be taken at the crash site, showed officials putting what they said were body fragments into bags for evidence.
It showed tattooed skin and said that, checked against DNA and identity records Russian authorities hold of Ukrainian prisoners of war, the investigation proved that those killed were Ukrainian soldiers.
Russia said on Friday it had recovered Ukrainian identity documents and tattooed body parts from the crash site near the Ukrainian border.
Ukraine did not immediately comment on the statement by the investigative committee.
