A top NATO official left Moscow this week after failing to make headway in the race against time to hammer out a deal giving Russia a voice in the affairs of the military alliance, Interfax reported.
NATO Assistant Secretary General Gunther Altenburg ended the latest round of negotiations on the make-up of a new "council of 20," grouping Russian and the 19 alliance members, on May 6, without clinching the deal due to be signed at a summit later this month, the news agency quoted diplomatic sources as saying.
Russia and NATO hope to seal their new-found partnership in the wake of last year's terrorist attacks on the United States by setting up the council to give Russia a real say in the alliance's strategy.
But the talks have run aground on Russia's insistence that the council of 20 must be a partnership of "equals," while NATO is keen to set limits on Russia's role.
"There are still some problems for Russia and NATO foreign ministers to tackle at a session of the Russia-NATO Joint Permanent Council in Reykjavik on May 14-15," the sources said after Altenburg's meeting with Russian Deputy Foreign Minister Yevgeny Gusarov.
A NATO spokesman here confirmed that Altenburg had left Moscow, adding that no other further talks were scheduled in the run-up to the Reykjavik meeting.
However, the Russian sources stressed that the latest round of talks had seen a "narrowing of positions on a number of issues," Interfax said.
Russian diplomatic sources said on May 4 that the two sides were close to striking a deal.
But that confidence was somewhat downgraded later, with Russian officials now talking only of "real chances" that the dispute could be settled in time for Russian President Vladimir Putin and NATO leaders to ink a deal at a Rome summit on May 28.
Altenburg's brief visit to Moscow was aimed at breaking the logjam in time for the 20 foreign ministers to approve the format of the new council when they meet in the Icelandic capital two weeks a head of the summit.
With only nine days to go to the Reykjavik meeting, there were still "difficulties" and a failure "to set aside certain stereotypes so that the new mechanism would be new in quality and not merely in name," Russian sources told Interfax.
"How to shape the new format of cooperation to make it perfectly clear that it is a '20,' not a '19-plus-one'" remains a key sticking point, other sources quoted by ITAR-TASS said.
"For this purpose it would be necessary to renounce the bloc approach before the sides coordinate their positions," and also "to decide whether or not to leave the Russia-NATO Permanent Joint Council as it is," the sources said.
Russia is dismissive of the council, or "19 plus one," which it regards merely as a talking-shop used to inform Moscow of decisions already taken by the NATO states.
Earlier a NATO source quoted by ITAR-TASS said that though the talks were "at the final stage" other meetings were still possible, as were new initiatives both at Reykjavik and Rome.
According to NATO officials, the new council of 20 will discuss a limited range of issues from anti-terrorism, arms proliferation, management of regional crises and peacekeeping to search-and-rescue efforts.
Under the new arrangement, Russia and the 19 NATO countries would meet formally as equals and decisions would be made by consensus, but NATO would be able to withdraw an issue from discussion if no agreement were possible and take it to its ruling body, the North Atlantic Council.
Putin, who has wholeheartedly backed the U.S.-led anti-terrorist campaign since September, is seeking to upgrade ties with NATO to obtain recognition of Russia's strategic position.
NATO, however, which is expected to invite up to another seven members from Central and Eastern Europe at a summit in November, remains suspicious that Moscow will try to undermine its collective security pact.