NATO and Russia have made little progress in talks to cooperate on a US-led missile shield for Europe, and failing a deal may have to drop plans for a summit in May, NATO's secretary general said Thursday.

Anders Fogh Rasmussen held out hope that the former Cold War foes will reach agreement before the 28-nation alliance holds its own summit in Chicago on May 20-21.

"However, I also have to make it clear that we have not made much progress so far," he said.

"We have had a lot of talks. These talks will continue. Maybe we will not have a clarified situation until a few weeks before the summit," Rasmussen said.

"We still keep it as an option to have a NATO-Russia summit in Chicago, but if there's no deal, probably there will be no summit."

Russia has also raised doubts about joining the summit, with the deputy foreign minister saying a decision would be taken after March 4 presidential elections expected to return Prime Minister Vladimir Putin to the Kremlin.

NATO and Russia agreed to explore ways to cooperate at a previous summit in Lisbon in November 2010, but the two sides have struggled to reach a deal.

Russia wants a legally-binding pledge that the missile shield will not threaten its strategic deterrent, but the alliance has refused, with the United States insisting that the system is aimed at countering Iranian missile threats.

NATO has also rejected Russia's demand to create a common anti-missile system, insisting instead on keeping two separate operations.

Russia has threatened to deploy missiles on the European Union's borders, citing concerns over plans to station US interceptors in Poland.

"I do believe that the Russian leaders will realise that it's also in their interest to cooperate with NATO on missile defence," Rasmussen said.