Alexander Lukashenko, the president of Belarus, told Russia's defence minister on Monday that he wanted guarantees that Moscow would defend his country if it was attacked, the state-owned BelTA news agency reported.
BelTA cited Lukashenko as making the remarks to Russian Defence Minister Sergei Shoigu during a meeting in the Belarusian capital Minsk.
Lukashenko was cited as saying that he had previously discussed the matter with Russian President Vladimir Putin who he said had agreed with him that such security guarantees were necessary and needed to be formalised.
"In general, it sounded at the talks (with Putin) that in the case of aggression against Belarus, the Russian Federation would protect Belarus as its own territory. These are the kind of security (guarantees) we need," Lukashenko was quoted as saying.
Belarus, which currently hosts a contingent of Russian forces, has offered assistance to Moscow during its military campaign in Ukraine which Russia calls "a special military operation."
In the war's earliest days, Minsk allowed Moscow to use its territory to launch an ultimately unsuccessful assault on the Ukrainian capital, Kyiv.
Since late last year, a flurry of military drills and visits from high-level Russian officials have sparked speculation that Belarus may formally join a new attack on Ukraine.
Lukashenko has consistently denied such intentions, but has said that Belarus will respond to any incursions onto its territory or attempts to foment unrest.
(Reporting by Reuters; editing by Andrew Osborn)