NATO is suspending all co-operation with Russia, because of Russia's occupation and annexation of the Crimea.
Foreign ministers of the alliance have urged Russia "to take immediate steps to return to compliance with international law".
After the meeting in Brussels on Tuesday, NATO and Ukraine announced they would intensify their co-operation and promote defence training in Ukraine.
Secretary General Anders Fogh Rasmussen said Russia's aggressive behaviour poses a threat to Europe's stability.
Earlier, NATO said it saw no sign that Russia was withdrawing troops from the Ukrainian border.
"Through its actions, Russia has undermined the principles on which our partnership is built and has breached its own international commitments. So we cannot go on doing business as usual," Mr Rasmussen said.
President Vladimir Putin told Chancellor Angela Merkel in a phone call on Monday he had ordered a partial withdrawal of Russian troops from the eastern Ukrainian border.
Ms Merkel said on Tuesday she had "no reason" to doubt his word.
But Mr Rasmussen said NATO saw no sign of this.
"Unfortunately, I cannot confirm that Russia is withdrawing its troops. This is not what we are seeing," he said.
Ukraine gas price raised
Gazprom has raised the price it charges Ukraine for gas by more than a third.
The Russian energy company says the change was because Kiev has failed to pay its bills.
Chief executive Alexei Miller said Ukraine's current debt to Russia stood at just over $US1.7 billion.
Russia previously offered Kiev a subsidy, but the BBC reports the political crisis in Ukraine has led to a deterioration in relations.
Mr Miller says the price of Russian gas for Ukraine has gone up to $385.50 per 1,000 cubic metres in the second quarter of 2014 from the previous rate of $268.50.
It will mean Ukraine paying more than the UK for gas, having previously paid less, according to calculations by ICIS, an energy price agency.
Its research shows the from 1 April Ukraine will pay 25.40 euros ($US35.04) per megawatt hour for gas.
That compares to 18.51 euros per megawatt hour that Ukraine previously paid.