Building a missile defense shield to cover all European countries, including Russia, would help restore confidence in NATO, the Bulgarian foreign minister said on Saturday. Nikolay Mladenov said that would show the people that "the Alliance is really taking care of their security rather than just engage in operations at the other end of the world."

Speaking earlier in the day at a NATO conference in Brussels, Secretary-General Anders Fogh Rasmussen called for a new Euro-Atlantic security architecture, "one security roof," in which Russia should be a full-fledged partner.

He said one security roof "would be a very strong political symbol that Russia is fully part of the Euro-Atlantic family, sharing the benefits and the costs - not outside, but very much inside."

He stressed that the new architecture should be aimed at countering the growing nuclear threat posed by rogue nations such as Iran.

Since the collapse of the Warsaw Pact, NATO has expanded from 12 members to 28, absorbing the majority of Moscow's Cold War allies in Eastern Europe and some former Soviet republics.

In February, Bulgaria and Romania said they were in talks with U.S. President Barack Obama's administration on deploying elements of the U.S. missile shield on their territories from 2015.

The move came after Obama scrapped last September plans by the Bush administration to deploy missile-defense elements in the Czech Republic and Poland due to a reassessment of the threat from Iran. Russia fiercely opposed the plans as a threat to its national security.