The Grad-model Katyusha rockets that were fired into Beersheba on Wednesday were manufactured in China and smuggled into Gaza after the Sinai border wall was blown up by Hamas in January, defense officials said. The Chinese rockets have a range of 40 kilometers. They are very similar to the 122 mm Soviet-made Katyusha that was used extensively by Hizbullah during the Second Lebanon War and are slightly more sophisticated than an Iranian-made Grad-model Katyusha that is also in Hamas's arsenal. The four rockets that hit Beersheba this week were filled with metal balls that can scatter up to 100 meters from the impact site, officials said. These rockets have also been fired into Ashkelon and Ashdod. The three countries that manufacture Grad-model Katyushas are China, Russia and Bulgaria. Defense officials told The Jerusalem Post the rockets were smuggled into Gaza in the 12 days after Hamas blew a hole in the border wall between Gaza and Egypt on January 23. "Huge quantities of weaponry were smuggled into Gaza then from above ground, including the Grad rockets," an official said, adding that even after the border wall was sealed, Hamas continued to smuggle the long-range rockets into Gaza via tunnels under the Philadelphi Corridor. From China, the rockets make several stops before reaching Gaza. In many cases, officials said, they are bought by Iran or Hizbullah and then transferred to Sinai. In some instances, the Shin Bet (Israel Security Agency) has learned of weapons that came from Yemen and Eritrea, were moved to Sudan, then north to Egypt, and finally smuggled into Gaza. "This is a complicated smuggling system that involves many different people around the world," one official said. The Grad-model Katyushas, officials said, were packed with large quantities of ammonia and less-than-maximum explosives to increase their durability and lethality. Last Thursday, Egyptian Foreign Minister Ahmed Aboul Gheit told Foreign Minister Tzipi Livni that Cairo was not responsible for Hamas's military buildup and that the long-range rockets in the group's arsenal were not smuggled through the tunnels from Sinai. Defense officials said Wednesday that Aboul Gheit was partially correct, in that some of the rockets did not come into Gaza through tunnels, but that they did enter the Strip from Sinai.