NATO foreign ministers have failed to ease Russian fears over a proposed missile defense shield in Europe.

NATO Secretary General Anders Fogh Rasmussen said Thursday the sides still have differences about the proposal but plan to keep talking. He also rejected Russia's claims the shield could be used against Russia.

Rasmussen spoke following a meeting with NATO foreign ministers and Russian Foreign Minister Sergei Lavrov at the alliance's headquarters in Brussels.

U.S. Secretary of State Hillary Clinton told reporters in Brussels that NATO's proposal to build a missile defense system in Europe should not be a cause for Russian military counter-measures. She said the proposal is not directed at Russia. The United States and NATO say the system is designed to help deter threats from countries such as Iran.

On Wednesday, Russia warned that the U.S. and NATO were forcing a new arms race by deploying a missile defense shield in Europe.

Last week, Russia officially opened a new anti-missile radar station in the Baltic Sea region of Kaliningrad.

Russia says it is willing to cooperate with the West and work together to share technology and jointly build a missile defense system — a proposal NATO has already rejected. Russian Chief of Staff General Nikolai Makarov questioned why NATO will not meet Russia halfway and suggested the alliance's refusal means it has something to gain from the shield.

Also on the agenda of the NATO meeting are alliance efforts in Kosovo and Afghanistan.