We kindly ask you to reassess the attitude of the US government towards the placement of NMD (national missile defence) elements in Europe and to put a stop to this dangerous project," they said in a letter obtained by AFP on Sunday.

If the US plans went ahead, they warned, "Europe will become the main battlefield in a potential international conflict."

The Bush administration has spearheaded efforts to build a radar facility some 70 kilometres (44 miles) from Prague, along with 10 interceptor missiles in Poland.

The US government says it would be used to warn off incoming ballistic missiles from "rogue states" such as Iran.

Obama has made no commitment to date on whether or not he would go ahead with the anti-missile system as president.

"The plan to place elements of this system in the heart of Europe is already increasing tension between the USA and Russia, as well as between USA and the European Union, and will lead to a new expansion of the arms race," the mayors said in their letter.

Two thirds of Czechs were against the shield, the mayors said, and "the current deputies were elected before there was any public discussion about the project, and the involvement of the Czech Republic in the NMD system was not the program of any political party."

The Czech government has called for a delay in a final vote on its radar agreements until Obama's inauguration in January.

The US missile plan has enraged Moscow, former Cold War master of Poland and the former Czechoslovakia. Russian President Dmitry Medvedev has vowed to deploy Iskander missile systems in its enclave of Kaliningrad in response.