Washington's deal to deploy part of a US missile defence system in Poland appears to be aimed against Russia, the Foreign Ministry said Friday.
"The agreement's content and the haste with which the two sides reached it allow the conclusion that the project is actually aimed against Russia," the Interfax news agency quoted a foreign ministry spokesman as saying, dpa reported.
Russian Foreign Minister Sergei Lavrov cancelled a planned September trip to Poland hours after the deal was struck Thursday, Poland's PAP news agency said.
Poland agreed to host US missile interceptors in return for military aid including Patriot air defence missiles. As part of the project, the Czech Republic agreed in July to host a US tracking radar.
Russia fervently opposes the missile shield, despite US assurances that it counters threats from countries like Iran and is too small to undermine Russia's nuclear deterrent, which comprises several thousand warheads atop long-range missiles.
The deal with Warsaw followed more than a year of tough bargaining and several years of informal US efforts to win agreement for building the system in the two former Soviet-bloc nations.
It also came less than a week after Russia's military assault in Georgia, which rallied key East European governments against Moscow.
The head of the Russian parliament's foreign affairs committee, Konstantin Kosachev, said the US-Polish deal would not boost security in Europe and could lead to "to a real increase in tension in Russian-American relations," Interfax reported late Thursday.
Poland bargained hard for US military aid, particularly for a boost in its air defences after Moscow threatened to target the planned missile-shield bases in its former satellites.
The interceptors are designed to destroy incoming intercontinental ballistic missiles in space. In contrast, the Patriots sought by Poland are theatre defence weapons with a range of about 70 kilometres.