Russia's ambassador to the United Nations on Tuesday accused Ukrainian intelligence services of aiding rebels fighting Syrian President Bashar al-Assad's government, saying some fighters were "openly flaunting" the association.
Rebels fighting with Islamist group Hayat Tahrir al-Sham (HTS) "have not only not concealed the fact that they are supported by Ukraine, but they are also openly flaunting this," Vassily Nebenzia told the Security Council. Russia is an ally of Syria.
The envoy said there was an "identifiable trail" showing Ukraine's GUR military intelligence service was providing weapons to fighters in northwest Syria.
"Ukrainian military instructors from the GUR are present... training HTS fighters for combat operations," including against Russian troops in Syria, said Nebenzia.
A renewed offensive in the past week, led by HTS and its allies, has seen a massive shift in the long-frozen frontlines of Syria's civil war, with the Islamist-led rebels advancing on Syria's fourth-largest city Hama after capturing Aleppo.
Russia's 2015 intervention in the Syrian civil war turned the tide in the Assad government's favor.
Amid the new offensive, a statement from Syria's army command said its forces were striking "terrorist organizations" in north Hama and Idlib provinces, with Russian air support.
- 'Utterly failed' -
Nebenzia also criticized UN officials for being "unable to summon the courage to call a spade a spade and to condemn these terrorist attacks" against Syria.
Deputy US ambassador Robert Wood refuted the criticism, saying: "the fact that HTS is listed as a terrorist organization by the US and UN does not justify the further atrocities by the Assad regime and its Russian backers."
Raed Saleh, director of the so-called White Helmets rescue group that operates in rebel-held parts of Syria, accused the international community of having "utterly failed the Syrian people."
"The Syrian people have appealed to you to take immediate action to end atrocities and ensure peace...however, in recent years, you have not only failed to heed these calls, but, tragically, many of your governments have chosen to forget Syria altogether," he said to the Security Council.
Saleh called out Moscow, urging it to end support for the Syrian government and for spreading "misinformation related to the White Helmets."
Ukraine's foreign ministry said Monday that Russia and Iran -- both supporters of Assad's hardline rule -- "bear the main responsibility" for the recent escalation in fighting.
Kyiv hit out at Assad for recognizing Moscow's annexation of the Crimean peninsula in 2014, and said Ukrainians were also being targeted on a nightly basis by Iranian-designed drones.
"The Russian dictator (Vladimir) Putin and his allies in Iran continue to make every effort not to lose control over the puppet Syrian regime, which is associated by the majority of Syrians with inhuman cruelty, tyranny and crimes," the ministry said.