Poland stepped closer to hosting US anti-missile rocket systems on its soil despite Russian objections by formally agreeing to start detailed negotiations with Washington.
The United States is building a global, multi-billion dollar "anti-missile shield" to shoot down ballistic missiles that could be launched by what Washington calls "rogue regimes".
Last month, it asked Poland and the Czech Republic to host parts of the system.
"The government expresses the intention to begin negotiations ..., declaring at the same time that any eventual agreement would have to strengthen US, Polish and international security," Poland's Foreign Ministry said in a statement.
The US plan irked Russia, which said the anti-missile system would upset the post-Cold War balance of power in Europe and threatened to pull out of arms control treaties in response. Washington says Russia has nothing to fear and rejected accusations, also levied by some of its European partners, that it had kept Moscow in the dark about the project until the last minute.
"We have briefed Russia extensively on the missile defence system," a US diplomatic official in Warsaw told Reuters. "The Russian defence minister has been given a full tour of one of the sites in Alaska so it was surprising that this wave of protests surfaced in the last couple of weeks."
The official said all European Nato partners had also been briefed on the project.
"We have made it clear that the system can at any time be incorporated into Nato's own defence," the official said.
Negotiations with Poland could start in the next few weeks. If they are successful, the site could be ready in three to four years.
Under the US proposal, Poland would host interceptor rockets shooting down hostile missiles in space while a powerful radar guiding them would be put on Czech territory. Up to 300 US troops would be stationed at the Polish base, a symbolic presence but one that officials in Warsaw believe would tie Poland even closer to the world's biggest superpower.
The conservative government says it also expects tangible US help in modernising its armed forces as part of the deal.
The Polish public is sceptical, however, with opinion polls showing most Poles fearing that hosting the anti-missile shield would make their homeland a target for terrorist attacks.
Prime Minister Jaroslaw Kaczynski's junior coalition partner, the leftist Self-Defence, also opposes the plan but analysts say the government is unlikely to fall over the issue. The government said parliament would have to ratify any deal on the missiles. Analysts said this would likely pass as the main opposition parties would back the plan.