The West yesterday blasted Moscow for unilaterally sending a controversial aid convoy to east Ukraine's rebel-held Lugansk in a move Kiev decried as an "invasion".
The European Union said it "deplored" Russia's decision to order in the convoy, which local officials said had arrived in Lugansk, without consent and called on Moscow to withdraw the trucks
Meanwhile, the UN Security Council was to hold snap consultations on the issue later yesterday and NATO chief Anders Fogh Rasmussen called Moscow's decision an escalation of the Ukraine crisis that "can only lead to Russia's further isolation".
The US called on Moscow to "immediately" withdraw the convoy. "Failure to do so will result in additional costs and isolation," Pentagon spokesman Rear Admiral John Kirby told reporters.
Russian President Vladimir Putin however said further delay of Moscow's mission would have been "unacceptable" as he justified the decision in a phone conversation with German Chancellor Angela Merkel, who travels to Kiev today for talks with Ukraine's leadership.
An official in Lugansk confirmed some 20 trucks had reached the centre of the city, which has been without water and power for weeks, after making their way along a perilous route from the border.
Ukraine's security service head Valentyn Nalyvaychenko earlier condemned the entry as "a direct invasion" but said Ukraine will not order air strikes on the trucks.
Ukraine and Russia both said the other side was responsible for the convoy's security between the border and rebel bastion Lugansk 63 kilometres away, and Russia's foreign ministry warned "against any attempts to disrupt a totally humanitarian mission".