Poland spurned as insufficient today a US offer to boost its air defenses in return for basing anti-missile interceptors on its soil but said it remained open to talks with Washington.
The decision by Poland, a staunch NATO ally, is a setback for the Bush administration drive to counter perceived threats from what Washington calls "rogue states," particularly Iran.
"We have not reached a satisfactory result on the issue of increasing the level of Polish security," Prime Minister Donald Tusk told a news conference after studying the latest US proposal.
"The aim of the negotiations, in my view, is to enhance the security of our country. We still agree that it is fundamental for us to maintain our alignment with the United States, which has been, is and will continue to be our strategic ally."
In Washington, the State Department said it was studying Mr Tusk's remarks closely.
"Poland remains a close and important ally of the United States," Sean McCormack, a department spokesman, said in an e-mailed statement. "We remain in negotiations with Poland and do not plan to comment publicly on the details."
Mr Tusk, without disclosing full details, said Washington was proposing to put Patriot batteries on Polish soil for one year.
In the months-long negotiations, Mr Tusk's center-right government had sought billions of dollars worth of US investment to upgrade Polish air defenses in return for hosting 10 two-stage missile interceptors.
"We are ready to accept proposals or corrections from the American side which would include our proposal to increase (our) security. We can do this in a day, a week, a month," Mr Tusk said.
The Czech Republic has agreed to host a tracking radar under the project. Its parliament has still to ratify the deal.
Russia has condemned the missile defense plan as a threat to its own security and has said it will target missiles at Poland and the Czech Republic - its communist-era satellite states - if the deployment goes ahead.