Nato announced it would send four additional battlegroups to strengthen its eastern flank and increase support to Kyiv, as Ukraine warned member states gathered in Brussels that Russia could also attack them.
"Russia's invasion of Ukraine has changed our security environment for the long term. It's a new reality, it's a new normal, and Nato is responding," Nato chief Jens Stoltenberg told journalists after the 30-member alliance met.
Nato will station four new multinational battlegroups, which usually number 1,000-1,500 troops, in Hungary, Slovakia, Romania and Bulgaria. This doubles the current number of battlegroups stationed along Nato's eastern flank.
Amid concerns that Moscow may be preparing to use chemical or biological weapons in Ukraine, the alliance warned this “would be unacceptable and result in severe consequences”.
“We are also enhancing allies’ preparedness and readiness for chemical and biological and nuclear threats,” Mr Stoltenberg told journalists.
Ukrainian president Volodymyr Zelenskiy addressed the summit by video link, and warned that the war could spread beyond his country if Russia was not stopped.
"I'm sure you understand that Russia does not intend to stop in Ukraine. Does not intend, and will not. It wants to go further, against the eastern members of Nato. The Baltic states, Poland – that's for sure," Mr Zelenskiy said.
Several Nato countries have announced they will ramp up military spending
He called for the alliance to give his military 1 per cent of their planes and tanks to help Ukraine in its fight, saying the country was in a “grey zone between the West and Russia” as he noted that previous calls for a no-fly zone to be imposed to prevent Russian aircraft bombing Ukrainian cities had not been fulfilled.
Mr Stoltenberg said that Nato members were “equipping Ukraine with significant military supplies including anti-tank, air defence systems and drones” and that this was “proving highly effective”.
Scope for action
However, he said that the alliance’s scope for action was limited by the need not to escalate.
“We have a responsibility to prevent this conflict from becoming a full-fledged war in Europe, involving not only Ukraine and Russia but Nato allies and Russia. That will be more dangerous and more devastating, and I think we have to be honest about that,” he told journalists.
In a statement, Nato called on China to "abstain from supporting Russia's war effort in any way" and "cease amplifying the Kremlin's false narratives".
It comes amid an international struggle to isolate Russia and stop wavering countries from helping Moscow to undermine the effect of sanctions. On Thursday, Taoiseach Micheál Martin described India’s position on bypassing sanctions as “unacceptable”, and called for New Delhi to “get off the fence”.
Several Nato countries have announced they will ramp up military spending. Belgium is expected to announce a major boost to defence spending, while the Estonian government announced it would increase its military budget by almost half a billion euro.
EU leaders meeting in Brussels on Thursday and Friday are set to give the final stamp of approval to a “strategic compass” plan to increase defence co-operation, including with a rapid response force of 5,000 troops.