PRAGUE, June 27 (Xinhua) -- Negotiations about the building of U.S. anti-missile defense system in Central Europe should be held within NATO, Bulgarian Foreign Minister Ivaylo Kalfin said after meeting with his Czech counterpart Karel Schwarzenberg on Wednesday.

    The states involved should follow a transparent policy on Russia in order to prevent Moscow from feeling threatened by the system, said Kalfin.

    According to Schwarzenberg, both the Czech Republic and Bulgaria agreed that the radar in the Czech Republic and a silo with ten interceptor missiles in Poland should become part of NATO's defense umbrella.

    Schwarzenberg said the Czech government would continue discussing the radar with Russia as well.

    "We are completely open in this respect," he said.

    The United States unveiled its plan in January to place a radar system in the Czech Republic and 10 interceptor missiles in Poland, as components of the missile defense shield. Russia has voiced strong opposition to the deployment.

    Bulgarian leaders said previously they want to ask NATO to include Bulgaria in the alliance defense system.

    As a NATO member country, Bulgaria is a firm ally of the United States. It has deployed its units in Iraq and Afghanistan. This year, some 2500 U.S. soldiers are to be stationed on Bulgaria's two bases.

    Kalfin and Schwarzenberg also discussed bilateral relations. Kalfin said that there are many opportunities for Bulgarian firms to invest in the Czech Republic.

    "We want to stimulate Bulgarian firms to invest abroad. I suppose that the Czech Republic will be one of these countries, " he said.

    Schwarzenberg said Bulgarian exports to the Czech Republic have been on the rise these days.