Israeli intelligence officials believe Hamas currently has, in Gaza, several hundred factory-made BM-21 rockets, each with a range of 20 km. They also have 6-km.-range B-12 rockets. The locally-made Kassam II has about the same range, but the B-12 is more reliable.
In 2002, Hamas began firing Kassam I rockets at Jewish settlements in Gaza and into southern Israel. By 2003, there was the Kassam II, with a range of 8 km. The Kassam III has a range of 10 km.
By June 2004, about 200 Kassams had been fired into southern Israel. By the end of 2005, over 400 Kassams had been fired at Israeli targets. In the next six months, another 600 rockets were fired. About a thousand Kassams were fired into Israel during 2006. This doubled, to two thousand in 2007, and during the first four months of 2008, another 2,000 were fired.
For every 30-40 Kassams fired, an Israeli is killed or wounded. Hamas has hopes that someday soon they will attack in conjunction with Hizbullah firing rockets into northern Israel, and Iran firing rockets into Tel Aviv.