WASHINGTON -- Using simple, inexpensive rocket technology dating from World War II, the Islamic militant group Hezbollah has opened a new chapter in the long-running Middle East conflict - showing that a decentralized guerrilla organization can partly counter the region's military superpower.
Despite Israel's overwhelming conventional force, Hezbollah has been able to fire more than 750 short-range rockets into northern Israel at will.
Hezbollah is relying heavily on variants of short-range Katyusha rockets, a weapon first produced by the Soviet Union in 1941 as a cheap metal tube stuffed with fuel at one end and explosives at the other.
All the models used by Hezbollah have one thing in common: They have no guidance system, and thus are utterly unpredictable.
"Katyushas are true terror weapons in the sense that where they hit is not clear, even to the people who fire them," said Loren Thompson of the Lexington Institute, a Washington defense think tank.
And because they are difficult to find before launch, Hezbollah rockets could trigger a long, destructive war that will require Israeli ground troops to enter southern Lebanon. Up to 13,000 such weapons are cached in southern Lebanon, Israeli military officials say.
More-sophisticated rockets have greater range and carry larger payloads. A model developed and built by Iran, the Fadjr-5, can carry a 385-pound warhead 46 miles, according to data from its manufacturer, Shahid Bagheri Industries in Tehran. Another missile, the Zelzal-2, is said to have a range of 124 miles.
The rockets pose a long-term threat that is difficult to counter.
Israel and the United States jointly developed a chemical laser that shot down 26 Katyusha rockets in tests at White Sands Missile Range in New Mexico in 2000 and 2001. But the weapon proved too costly and cumbersome to defend against cheap rockets that can be fired in salvos of dozens at a time.
"That's the great problem with the multiple rocket threat: Anything you use to shoot them down will cost more than the rockets themselves," said David Isby, a Washington-based defense and foreign policy consultant.
"In the end, I think the Israelis will have to do what the British did with the German V-2 rockets in World War II - go in and destroy the problem at its source," Thompson said.
In 1944, Germans fired 141 of the 13-ton V-2 rockets at London, causing damage and public panic as they fell without warning. Unable to defend against the primitive rockets, British and Allied bombers eventually destroyed the launch sites in the occupied Netherlands.
No such easy solution is possible in Lebanon, experts say, because rather than employing fixed launch sites, Hezbollah is using mobile launchers.
Fixed sites require concrete pads and launch rails for the heavier rockets, structures that could be seen and targeted from the air. But Hezbollah seems to have hidden its rockets, sometimes under brush or in garages. Most variants of the Katyusha can be set up and fired in less than an hour, said John Pike, a military technology expert at GlobalSecurity, a Web-based defense research organization.
The Iranian-built Fadjr-5 takes well over an hour for its truck-mounted launcher to be set up and adjusted, Pike said. But according to Iran's Aerospace Industries Organization, the launcher can then fire its four rockets in just over 30 seconds.
Israel uses counter-battery radar that can locate the launch site by analyzing the trajectory of an incoming rocket.
Israeli aircraft and unmanned drones search for the telltale flash of a missile launch, but such efforts are often stymied by Hezbollah's practice of setting up a primitive launcher, connecting a car battery and a timer, and leaving the rocket to launch on its own.
"I suspect that's how many of them are fired, because anyone standing near a launch site two minutes later will get all sorts of Israeli artillery on their head," Isby said.
Because of these factors, Hezbollah's rocket force probably cannot be destroyed from the air.
"It means not only continuous and heavier bombing, but probably putting troops on the ground," Thompson and other military analysts say.
What little guidance the rockets have is applied before they are launched, by pointing them in the right direction and elevating them to gain or lose distance. A chart supplied by its Iranian manufacturer shows the Fadjr-5 pointed high from its truck launcher to achieve an altitude of 95,000 feet before angling down sharply to impact 46 miles away. A lower trajectory presumably would gain distance.
Any number of variables - wind, fuel variations or an error in elevation or direction - can cause the rocket to land far from its intended target.
But one indication that the rockets are intended as weapons of terror is that no Israeli military targets have been struck so far, Isby said.