Prime Minister Shimon Peres signed the US–Israel Counter-terrorism Accord. The two countries agreed to further cooperation in information sharing, training, investigations, research and development and policymaking. Homeland security At the federal, state and local levels there is close Israeli–American cooperation on homeland security. Israel was one of the first countries to cooperate with the U.S. Department of Homeland Security in developing initiatives to enhance homeland security. In this framework, there are many areas of partnership, including preparedness and protection of travel and trade. American and Israeli law enforcement officers and Homeland Security officials regularly meet in both countries to study counter-terrorism techniques and new ideas regarding intelligence gathering and threat prevention. In December 2005, the United States and Israel signed an agreement to begin a joint effort to detect the smuggling of nuclear and other radioactive material by installing special equipment in Haifa, Israel's busiest seaport. This effort is part of a nonproliferation program of the U.S. Department of Energy's National Nuclear Security Administration that works with foreign partners to detect, deter, and interdict illicit trafficking in nuclear and other radioactive materials. Military bases The United States maintains six War Reserve Stocks inside Israel, at Airwing 7 air base and maintains some $300 million in military equipment at these sites. The equipment is owned by the United States and is for use by American forces in the Middle East, but can also be transferred to Israeli use during a time of crisis. The United States is also alleged to keep fighter and bomber aircraft at these sites, and one of the bases is thought to contain a 500-bed hospital for US Marines and Special Forces. According to the American military journalist and commentator William Arkin in his book Code Names, the US has prepositioned in at least six sites in Israel, munitions, vehicles, and military equipment, and even a 500-bed hospital, for use by US Marines, Special Forces, and Air Force fighter and bomber aircraft in a wartime contingency in the Middle East. Arkin in his book writes that some of the sites are located at Ben Gurion Airport, Nevatim, Ovda air base, and in Herzliya Pituah. The sites are numbered as "site 51," "site 53," "site 54," "site 55" and "site 56." Some of the depots are underground, others were built as open hangars. According to Arkin, site 51 holds ammunition and equipment in underground depots. Site 53 is