In a move expected to heighten tension in the Middle East, the Obama administration is quietly expanding its land- and sea-based missile shield system in the Persian Gulf region. The US is dispatching Patriot defensive missiles to Qatar, United Arab Emirates, Bahrain and Kuwait. In addition, the US is keeping two ships in the Gulf capable of shooting down missiles. The Obama White House says the move is aimed at deterring an attack by Iran. In addition, Washington is helping Saudi Arabia to create a 30,000-strong force to protect oil installations and other infrastructure.