In 2004, the Harpy became the focus of the effort by the United States to restrict arms transfers and the sales of advanced military technology to China. Sold to China in 1994 for around $US 55 million, the UAVs were returned to Israel in 2004 under contract to be upgraded. The United States demanded that Israel seize the UAVs and nullify the contract. According to Israel, the Harpy is an indigenously designed UAV. It does not contain any US-produced sub-systems. In 2005, the UAVs were returned to China without being upgraded. This incident chilled relations between the United States and Israel, with Israel being suspended from its status as Security Cooperative Participant in the Joint Strike Fighter program. As of November 6, 2005, however, Israel has stated that it has been re-admitted into the program.