Niger has cut diplomatic ties with Ukraine, a move which signals a burgeoning rift between some West African states and Kyiv.
Niger's military government said it made the move in "solidarity" with neighbouring Mali, who severed their own relations with Ukraine two days ago.
Both countries cited comments by a Ukrainian military official, who suggested Kyiv played a role in the killing of dozens of Malian soldiers last month.
Ukraine has been trying to win allies in Africa throughout its war with Russia, likely in an attempt to counter Moscow's growing influence on the continent.
At the end of July, scores of Malian soldiers, along with mercenaries from Russia's Wagner group, were killed in clashes with separatist rebels and al-Qaeda-linked militants.
Mali's military regime had turned to the notorious Wagner group in 2021, seeking support in tackling its crippling insecurity issues.
After Wagner confirmed "losses" in July's attack, Andriy Yusov, a spokesman for Ukrainian military intelligence, said the rebels received "the necessary information they needed" to conduct the attacks.
He did not elaborate.
In response to Mr Yusov's comment, Mali accused Ukraine of violating its sovereignty and announced it was breaking off relations with Ukraine "with immediate effect".
Niger followed suit on Tuesday, with government spokesman Amadou Abdramane calling Mr Yusov's remarks "unacceptable".
Mali's neighbour Senegal also rebuked Ukraine.
Over the weekend, Senegal's foreign ministry summoned Ukraine’s ambassador, Yurii Pyvovarov, accusing him of supporting July's attack in Mali in a since-deleted video posted on the Ukrainian embassy’s Facebook account.
Ukraine's foreign ministry has not yet commented on Niger's decision to sever diplomatic ties.
However, it called Mali's decision "short-sighted and hasty", and said Ukraine "unconditionally" complies with international law and accused Russian-controlled outfits of "numerous war crimes" in African countries.
Russia weighed in on the matter on Wednesday, accusing Ukraine of opening a "second front" in Africa.
"The regime of [Ukrainian President] Zelensky is pandering to terrorist groups in countries on the continent friendly to Moscow," Russian foreign ministry spokeswoman Maria Zakharova told the RIA Novosti news agency.
In recent years, Mali, Niger and Burkina Faso have undergone coups and their new military government's have ripped up defence agreements with France and the US, preferring military help from Russia.
As Russia's popularity on the continent expands, Ukraine has attempted to strengthen its ties with African nations.
Ukrainian foreign minister Dmytro Kuleba is currently on his fourth visit to Africa in the last two years - this time he is visiting Malawi, Zambia and Mauritius.
Presently, it is hard to tell whether other West African countries might follow Niger and Mali in cutting ties with Ukraine.
Many will be waiting to see the reaction of Burkina Faso, which formed a bloc with Niger and Mali earlier this year and is also ruled by the military.
West Africa is not the only region to be impacted by the Ukraine-Russia war.
In Sudan, Wagner is alleged to be backing the paramilitary Rapid Support Forces (RSF), which has been at war with the Sudanese army for more than a year now.
Meanwhile, widely circulated videos show what is reported to be Ukrainian special forces carrying out drone strikes, and other armed attacks, against the RSF and Wagner fighters in Sudan.
The BBC has not been able to verify these videos.
As Russia and Ukraine's war continued to play out in Africa, more than 70 mourners gathered in Moscow to pay homage to the Wagner fighters killed in July's attack.
Red carnations were laid below pictures of fallen fighters at a memorial on Sunday, press agency Reuters reported, while some attendees lit candles.