NATO chief Anders Fogh Rasmussen said Friday he could no longer trust Russia's assurances on the territorial integrity of countries in the region after its annexation of Crimea.
"After what we have seen in Ukraine, no one can trust Russia's so-called guarantees on other countries' sovereignty and territorial integrity," Rasmussen told a press conference during a visit to Romania.
NATO's secretary-general was referring to remarks by Russian officials saying Moscow would observe Moldova's territorial integrity provided the former Soviet republic remained neutral and offered a special status to the breakaway region of Transdniester.
In an interview with Romanian website HotNews.ro Thursday, Rasmussen said he expected Moscow to increase pressure on Moldova and Georgia, as the two ex-Soviet satellites prepare to sign an Association Agreement with the European Union on June 27, a move angering Russia and Russian-speaking Transdniester.
He said Russia aimed to prevent its former satellites having closer ties with the EU and NATO.
"In 1994 Russia guaranteed the territorial integrity and sovereignty of Ukraine and what we have seen recently is ... a grab of land by force, an illegal annexation of Crimea," Rasmussen said in Bucharest.
He added that every nation has a right to decide its alliances, and urged Russia "to live up to its international obligations and not try to destabilise the situation, neither in Moldova nor in Ukraine."
Ukrainian prime minister Arseniy Yatsenyuk's recent warning of a third world war breaking out were "a bit dramatic", Rasmussen said.
NATO had already reinforced the collective defence of its members and "will not hesitate to take further steps" in that respect if needed, he added.