Russian missiles kill 35 as refugee concerns grow

The escalation in western Ukraine also came amid a report in the Financial Times that Russia may ask China to supply it with weaponry, potentially aggravating geopolitical tensions over the war.

Yavoriv itself is near railway lines being used by thousands of women and children riding on densely packed trains from Lviv, in western Ukraine, to the Polish town of Przemyśl, to flee the war.

Yavoriv is also just 10km from the Polish border and less than 100km from the city of Rzeszów in south-east Poland — a Nato state where the US installed two Patriot anti-missile batteries at the city's airport last Wednesday in a sign of concern the Russian war was creeping closer.

If Russia were to cut Lviv off from Poland, that would likely trap refugees in the expanding war zone, where Russian forces already stand accused of large numbers of civilian deaths.

Cutting off Lviv would also close off one of the main routes used by pro-Ukraine allies for deliveries of anti-tank and anti-aircraft weapons to the Ukrainian military.

Ukraine's Yavoriv base hosted "foreign instructors," the Ukrainian foreign ministry said Sunday, without giving their nationalities.

There were "no Nato personnel" in Yavoriv or anywhere else in Ukraine, a Nato official told Reuters the same day.

But if Nato states' forces were taking part in covert arms convoys to Ukraine, they would be "legitimate targets," Russia's deputy foreign minister Sergey Ryabkov said Saturday.

Nato voiced ongoing support for its members' arms-to-Ukraine program despite the increasingly dangerous environment.

"Ukraine has the right to self-defence," a Nato official told EUobserver after the Yavoriv missile bombardment. "As Ukraine bravely resists the invasion, Nato allies continue to provide support, including military, humanitarian and financial assistance."

If Russia were to accidentally or deliberately hit Polish soil, it would pose a dilemma for the allies about how to retaliate while avoiding an escalation involving nuclear adversaries.

But Nato, which has fighter jets policing the Polish-Ukraine border and a multinational battalion in Orzysz, north-east Poland, vowed a firm response Sunday if Russia crossed the line.

"Nato will defend every inch of allied territory," the Nato official said.

Chemical and biological fears

Also Sunday, Nato secretary general Jens Stoltenberg warned of the prospect of Russian escalation inside Ukraine in an interview published by German newspaper Welt am Sonntag.

Russia had been making "absurd claims" about US-sponsored chemical and biological weapons factories in Ukraine, he said. And "we must remain vigilant because it is possible that Russia itself could plan chemical weapons operations under this fabrication of lies."

Sunday was the 18th day of the war and it was was marked by shooting dead of an American journalist, Brent Renaud, by Russian soldiers while he was filming refugees in Irpin, near Kyiv.

The killing came as EU countries put the finishing touches on a next round of economic sanctions on Russia, which could include a ban on exports of European luxury items.

But for some security insiders, Renaud's death was a sign that international sanctions were so far having little effect on Russian actions in Ukraine.

"Russian behaviour on the ground in Ukraine is becoming increasingly brutal and reckless with each day the conflict goes on," said one intelligence officer from a Nato member country who asked to remain anonymous. "We're now seeing things that we previously thought were beyond the pale, like targeting of Western journalists," the officer said.

"Why not? They are capable of anything," a second intelligence officer, from Ukraine, replied when asked if there was a threat of a Russian false-flag chemical attack or even small-scale nuclear attack in Ukraine.

Ukraine needed more Western anti-aircraft defences to "close the sky" to Russian air power, the Ukrainian intelligence officer said.

But, he said, the best prospect of a peaceful outcome lay in even more severe EU and US economic sanctions, leading to internal regime change in Russia. "This is everybody's best hope."