Beijing has returned a U.S. underwater drone seized last week in the South China Sea by a Chinese Navy vessel after "friendly" talks between the two countries, China's Defense Ministry said in a short statement posted to its website Tuesday.

"After friendly consultations between the Chinese and U.S. sides, the handover work for the U.S. underwater drone was smoothly completed in relevant waters in the South China Sea at midday on Dec. 20," the statement said.

The Pentagon confirmed the handover, but criticized the Chinese Navy over the move.