The Israeli air force is considering phasing out its U.S.-built Raytheon Hawk surface-to-air missiles, backbone of its air-defense network since 1965, and replacing them with David's Sling, a weapon being developed by Rafael Advances Defense Systems.

The Jerusalem Post reported Monday that, according to military planners, the first battery of David's Sling, which is designed to intercept medium-range missiles, should be operational in 2012.

However, the ultimate aim appears to be to adapt David's Sling to counter aircraft as well as missiles.

The Jerusalem Post gave no details on that but quoted a senior air force officer as saying that even once David's Sling has been declared operational in its original role of providing a defense against missiles with ranges of 43-187 miles, "it will still take some time before it is formatted to also defend against enemy aircraft."

The system uses an interceptor called Stunner, which is considered capable of countering Iranian missiles such as the M600, the Zelzal, Fajr and Fateh 110, hundreds of which are reportedly deployed with Hezbollah in Lebanon.

Each David's Sling launcher holds 16 missiles, which operate with an advanced phased-array radar made by state-owned Israel Aerospace Industries.

IAI also manufactures the high-altitude, long-range Arrow-2 missiles that is designed to shoot down ballistic missiles such as Iran's Shehab-3b, currently the mainstay of its strategic missile force.

David's Sling and Arrow-2 -- a more advanced Arrow-3 variant is being developed -- comprise the middle and top layers of a planned three-tier missile defense system.

This has become a critical element in the Israeli arsenal. Iran is reckoned to have more than 100 Shehabs in operation. Syria, its Arab ally, has an estimated 850 guided missiles.

By Israeli count, the Iranian-backed Hezbollah in Lebanon has 50,000 missiles and rockets, while the Palestinian radicals of Hamas in the Gaza Strip, on Israel's southern flank, have an estimated 5,000 short-range rockets.

Arrow has been operational since 2000 but is untested in action.

The bottom-tier system, Iron Dome, also built by Rafael, made its combat debut in early April. It shot down eight out of nine Grad-type rockets launched by Palestinian militants in the Gaza Strip against the cities of Ashkelon and Beersheba.

Its central computer tracks every incoming missile or rocket and is programmed to ignore those whose trajectories indicate they won't hit populated areas.

There are only two batteries of Iron Dome deployed but the military plans to spend $1 billion to produce up to 15 more batteries to protect Israel's population centers.

These have become vulnerable to missiles and rockets fired from Iran and Syria as well as short-range weapons unleashed by Hezbollah in Lebanon and Hamas in Gaza.

If the plan to replace the venerable MIM-23 Hawks goes ahead, it will mark the end of an era.

The Hawk, a medium-range surface-to-air missile, was first deployed in Israel in March 1965 and remains the main ground-based defense against aircraft. It was initially designed to kill aircraft but was adapted to destroy missiles in flight as well -- the reverse of David's Sling.

The Hawk's first kill was scored in unusual circumstances on June 5, 1967, the first day of the Six-Day War. A MIM-23A shot down an Israeli Dassault MD450 Ouragan jet that was in danger of crashing into the nuclear research center at Dimona in the Negev Desert. It was the first time the system had been fired in combat.

During the War of Attrition between Israel and Egypt from March 1969 to August 1970, Hawks shot down 8-12 Egyptian aircraft. The system was extensively used during the three-week October 1973 war against Syria and Egypt and shot down 12-24 Arab aircraft.

The Israeli air force has 17 MIM-23B Improved Hawk batteries operational.