Yusov had said Malian "rebels" had
received necessary information "to conduct a successful military operation".
Mali and Niger interpreted Yusov's comments as an admission of Ukraine's direct involvement in the conflict, and accused it of supporting international terrorism as a result.
Ukraine has
repeatedly called the allegations groundless and untrue. Its foreign ministry did not immediately respond to a request for comment on Wednesday. The country is still locked in heavy fighting with Russia more than two years after Moscow's invasion.
Both ethnic Tuareg separatists and jihadist insurgents operate in north Mali. The Tuareg said they had killed at least 84 Wagner mercenaries and 47 Malian soldiers over days of fierce fighting in July.
An al Qaeda affiliate separately said it had killed 50 Wagner mercenaries and 10 Malian soldiers in an ambush on one of those days.
In their letter to the Security Council, the foreign ministers of Mali, Niger and Burkina Faso asked it to "take responsibility" for Ukraine's actions and to prevent "subversive acts" that threaten regional and continental stability.
The letter's text was posted on the Malian foreign ministry's social media account. Diplomats said it was circulated to the 15-member Security Council on Tuesday evening.
Burkina Faso, Mali and Niger have turned their backs on traditional Western and regional allies in favour of Russia since their juntas took power over the past four years.
The July attacks, which took place in Mali's northern Kidal region near the border with Algeria, are potentially Wagner's heaviest defeat since it stepped in two years ago to help the junta fight jihadist insurgents.
The ethnic Tuareg are a separate group who inhabit the Sahara region, including parts of northern Mali. Tuareg-led separatists launched a rebellion in 2012 that was pushed back into Mali's arid north and later hijacked by Islamist militant groups.
Source : Reuters