The US military has deployed the THAAD missile defense system in Israel, according to Defense Secretary Lloyd Austin. The system is now 'in place' and adds to Israel's existing anti-missile defenses. It was sent to protect Israel in case of an Iranian reaction to an expected Israeli reprisal attack. The THAAD system is considered a complementary system to the Patriot system and can defend a wider area. The deployment of the system deepens the US's involvement in the conflict and puts US troops at risk.