"We believe that the attack is absolutely illegitimate though it formally was in accordance with law," No to Bases spokesman Jan Majicek said during the protest staged outside the seat of the Military General Staff.

Majicek said the Greenpeace protest symbolized the opinion of the majority of Czech population who are against the base.

Opinion polls have repeatedly confirmed that most Czechs oppose the project.

Greenpeace activists blocked the planned US radar site in the Brdy military district, known as the spot height 718, for six weeks to protest against the US project. Czech soldiers started transferring the Greenpeace activists away from the spot height 718 on Monday.

The military began to fence off the spot height 718, which is situated some 90 km southwest of capital Prague, yesterday.

It is not yet clear how large the area will be fenced, but it is assumed that the fence will be several kilometer long, military police spokesman Jan Cermak said, adding that the military will guard the area even when fenced off.

The United States plans to build a radar base in the Czech Republic, along with an interceptor missile base in Poland.

Russia is strongly opposed to the deployment of the system, saying the plan poses a threat to its strategic interests. Some 70 percent of Czech citizens also oppose the project.

Topolanek's center-right government has completed its talks with the United States on the main radar treaty and it is reportedly close to completing negotiations on the complementary SOFA treaty, dealing with US soldiers' status on Czech territory.