A number of Palestinian terror cell members have recently left the Gaza Strip and traveled abroad to learn how to manufacture and effectively launch short-range Katyusha rockets, high-ranking defense officials told The Jerusalem Post on Monday. According to the officials, the new rockets, with an estimated range of over 35 kilometers, could reach the southern cities of Kiryat Gat, Netivot and Ofakim. A senior IDF officer said the terrorists who traveled abroad were those responsible for the development and firing of Kassam rockets at the western Negev. The terrorists have decided, the officer said, to begin using Katyusha rockets against Israel, since the Kassam has exhausted itself technologically. "The Kassam cannot be further upgraded, and the Palestinians need a new weapon," the officer said. "The cells have traveled abroad to learn about the Katyusha rocket and how to manufacture it back in the Gaza Strip." While the officer refrained from revealing the cell members' destination, Hamas terrorists have been known to travel to Lebanon and Iran for training with Hizbullah and the Iranian Revolutionary Guards. While the Kassam has been the IDF's current and immediate focus, a high-ranking defense official said Monday that it was necessary to begin preparing for the possibility that the Palestinian terror organizations in the Gaza Strip would also soon obtain rockets with even longer ranges than that of the Katyusha. Palestinian terrorists in Gaza are also known to have a small quantity of old Soviet-era Grad-type Katyusha rockets, some of which have been fired at Israel - although without reaching their maximum range of close to 30 kilometers. During the war in Lebanon, close to 4,000 rockets - mostly short-range Katyushas - landed in northern Israel. As a result of the new intelligence, the Home Front Command has stopped formulating protection and defense plans based on the Kassam threat, and has updated all of its databases and now runs simulations and tests protective measures against the larger Katyusha rocket. In May, the Islamic Jihad claimed responsibility for a Katyusha rocket attack on the Gaza-belt community of Netiv Ha'asara. Unlike the homemade, short-range Kassam rockets frequently launched at Israel, Islamic Jihad said the Grad version of the Katyusha was 2.8 meters long, weighed 66 kilograms and had a caliber of 122 mm. It carried a 17-kilogram warhead, the group said, and had a range of 18 to 30 kilometers.