Nato warns of Russian chemical weapons threat

They also agreed to send chemical, biological, radiological, and nuclear protective equipment to Ukraine and to share know-how on crisis management in case it was needed.

Allies' concern was mounting because Russian propaganda has been laying the groundwork for a false-flag attack on Ukraine using internationally banned weapons, Nato secretary general Jens Stoltenberg said after Thursday's meeting.

"Any use of chemical weapons will totally change the nature of the conflict," he said.

"There's also a risk that it will have a direct effect on people living in Nato countries, because we can see contamination, we can see the spread of chemical agents or biological weapons into our countries," he added.

And Russia had a track record of chemical weapons use in the UK, Syria, and inside Russia itself, Stoltenberg noted.

Thursday's emergency Nato summit was called one month after Russia invaded its neighbour and began pounding Ukrainian cities with conventional firepower to try to break resistance. It comes on the same day as EU leaders held a summit and the leaders of the G-7countries also gathered in Brussels in a show of unity.

The Nato meeting saw Ukrainian president Volodomyr Zelensky address Western leaders by video-link from Kyiv. Zelensky spoke "eloquently" and appealed for more Western arms supplies, a US official told press.

US president Joe Biden also spoke of Russia's "brutal war" and promised Ukraine "significant, and increasing, amounts of security assistance to fight Russian aggression and uphold their right to self-defence" in a brief statement to media.

There were "very credible reports about the use of military force against civilians" Nato's Stoltenberg said.

And Western allies would continue to supply anti-tank and anti-aircraft weapons and drones to Ukraine despite Russia's aggressive rhetoric about outside interference Stoltenberg noted.

"[Russian president] Vladimir Putin has already crossed the red line into barbarism," UK prime minister Boris Johnson also said.

Thin blue line

Despite the moral outrage, Western allies have categorically ruled out sending their soldiers into Ukraine in any role, such as peacekeepers, in order to avoid a Russia-Nato confrontation.

"We have a responsibility to ensure that this conflict does not become a full-fledged war between Nato and Russia," Stoltenberg said on Thursday.

"We will not deploy troops on the ground in Ukraine because the only way to do that is to be prepared to engage in full conflict with Russian troops," he said.

Nato already has 40,000 soldiers in four multinational battalions in the Baltic states and Poland in order to deter Russia from aggression against Nato territory.

The US also has some 100,000 soldiers stationed in Europe for the same reason.

The Allied measures designed to deter Russia also include warplanes on air-policing flights, anti-missile systems, and warships and submarines from the High North to the Mediterranean Sea, Stoltenberg said on Thursday.

And when Nato leaders meet again in Madrid in two months' time, they will detail plans to send some 40,000 more troops to new Russia-deterrent battalions in Bulgaria, Hungary, Romania, and Slovakia in future.

"So this is long term," Stoltenberg said. "We are prepared for the long haul because we can already say today that the Russian invasion, president Putin's invasion of Ukraine has changed our security environment," Stoltenberg said.

The war was the "gravest threat to Euro-Atlantic security in decades", the Nato leaders' joint statement said.