WASHINGTON (AP) -- Recent government reports warn that the Obama administration's missile defense shield in Europe faces major delays, cost overruns and critical technological problems.

The reports by the Defense Department and congressional investigators cast doubt on a program that is at the core of American plans to defend Europe and a sensitive political issue both domestically and in relations with Russia.

They say missile interceptors are running into production glitches, the systems' radars are underpowered and the sensors cannot distinguish between warheads and other objects.

Some Republicans have seized on the reports, saying it backs their view that the program was hastily designed to ease the concerns of Russia. Moscow had objected to previous plans by the Bush administration.

The administration insists the plans are on track.