Syria's Al Watan newspaper reports that it has confirmed this story. According to the story, Hezbollah is in possession of missiles with a range of 300 km, which is about the distance necessary to shoot from north of the Litani river to Ashkelon.
This would be consistent with a recent Aviation Week story that discusses this weapon:
Israel is growing increasingly concerned about the deployment of Syrian-made M-600 missiles in Lebanon that are capable of accurately striking any point in Israel.
The 600-mm. solid-fuel M-600, which carries a 500-kg. (1,100-lb.) warhead, is a Syrian improvement to Iran’s Fateh-110 missile and has a range of more than 300 km. (185 mi.). But perhaps more critically, the weapon is fitted with a GPS-aided inertial navigation system, giving it an accuracy of better than 200 meters (655 ft.) circular error probable (CEP). This means that half the missiles fired will fall within a 200-meter circle of the intended target.
While Israel has been exposed to rocket fire for some time, those weapons have been largely unguided, minimizing the extent of damage. With the M-600, that could now change.
The combat arm of the militant Hezbollah organization has already deployed around 200 M-600 missiles in Lebanon, according to data presented by Avner Raz, chairman of Israel Military Industries, who spoke at the first international anti-ballistic missile conference in Israel on May 5.
“With that missile, Hezbollah is turning from a terror threat to a military one,” Uzi Rubin, former director of Israel’s ballistic missile defense organization told Aviation Week. “Hezbollah could shut down electricity and airports in Israel, obstruct the operation of the Israeli air force or the mobilization of the reserve army, and even interfere with the functionality of the General Staff in Tel Aviv.”
This entire discussion of Hezbollah weapons was somewhat sidetracked by Israeli president Shimon Peres' statement last month that Syria has supplied Hezbollah with Scud missiles. Hezbollah and Syria denied that accusation, and UNIFIL stated that they weren't aware of any Scuds.
Now, however, it sounds like Israel, Syria and Hezbollah all agree that Hezbollah is now in possession of the M-600 - a much more sophisticated weapon than the somewhat outdated Scuds.