Russia said on Tuesday it would insist that Western governments respect a 1999 agreement that no country can strengthen its own security at the expense of others, an issue it argues is at the heart of the Ukraine crisis.
Foreign Minister Sergei Lavrov said he raised the matter in a conversation with U.S. Secretary of State Antony Blinken, and that Blinken accepted the need to discuss it further.
In the U.S. readout of the call, the State Department said Blinken urged Russia to immediately pull back troops from Ukraine's border and said Washington was willing to continue talking about mutual security concerns.
Lavrov told reporters that Russia's stance was based on a 1999 charter signed in Istanbul by members of the Organisation for Security and Cooperation in Europe, which includes the United States and Canada.
The charter says countries should be free to choose their own security arrangements and alliances, but goes on to say that they "will not strengthen their security at the expense of the security of other states".
Russia accuses the West of doing precisely that by expanding NATO eastward since the Cold War and refusing to rule out granting membership to Ukraine. NATO says it is a defensive alliance that is open to new members.
"Our western colleagues are simply trying not even to ignore but to consign to oblivion this key principle of international law agreed in the Euro-Atlantic space," Lavrov told reporters.
He said he had told Blinken that Russia would not let the matter drop. "We will insist on an honest conversation and an honest explanation of why the West doesn't want to fulfil its obligations, or wants to meet them only selectively to its own advantage."
Russia's Foreign Ministry said Lavrov had written to the United States, Canada and a number of governments on Jan. 28 to ask them urgently to explain how they intended to fulfil this commitment to the principle of "indivisible security".
Russia has yet to give its response to U.S. and NATO letters last week that rejected key security demands by Moscow but expressed willingness to hold talks on arms control and confidence-building measures.
(Writing by Mark Trevelyan; editing by Grant McCool)