NATO Secretary General Anders Fogh Rasmussen has said he could no longer trust Russia’s assurances on the territorial integrity of nations in the region after developments in Ukraine.
Rasmussen made the comments at a press conference on Friday during an official visit to an alliance member, Romania, which shares borders with Ukraine.
"After what we have seen in Ukraine, no one can trust Russia's so-called guarantees on other countries' sovereignty and territorial integrity," said Rasmussen.
The NATO chief also said in the wake of the crisis in Ukraine the alliance has reinforced the collective defense of its members and "will not hesitate to take further steps" in that respect “if needed.”
On April 30, a NATO member, Canada, deployed six fighter jets and hundreds of troops to Romania as part of its contribution to the alliance’s military presence in eastern and central Europe.
Tensions between Russia and the West heightened after Ukraine's former Black Sea peninsula of Crimea joined the Russian Federation following a referendum on March 16.
Since then two other regions in eastern Ukraine, Donetsk and Lugansk, declared independence following local referendums, in which the regions’ residents voted overwhelmingly in favor of independence from Kiev.
The United States and its European allies have accused Russia of violating Ukraine’s sovereignty by stirring up pro-Russia protests in eastern Ukraine.
Russia has repeatedly denied the allegation, saying the protests have begun spontaneously against what it calls the illegitimate interim government in Kiev.