Israel's volatile front with Gaza, a crowded seaside strip along Israel's southwest flank, has been largely quiet since an Israeli military offensive three years ago. The operation, launched in response to heavy barrages of rocket fire, killed about 1,400 people, including hundreds of civilians, and inflicted heavy damage on Hamas.
But since then, Hamas has restocked its arsenal, and fighting has sporadically flared up, most recently late last month when one Israeli and 10 Gaza militants were killed over several days of violence.
Hamas officials did not immediately respond to requests for comment.
Hamas, along with smaller militant groups, now possesses sophisticated antitank and antiaircraft weapons, the official said. He said members also have rockets capable of reaching the northern suburbs of Tel Aviv, roughly 50 miles from Gaza, meaning that Israel's main population center is now within range.
The official said many arms have flooded into Gaza since the Libyan revolution, with looted weapons making their way through Egypt's Sinai Peninsula and into Gaza through the border tunnels. He said the weapons shipping was taking place despite improved efforts by Egypt's new government to stop the smuggling.
He said the weapons have not changed militants' abilities, since armed groups already possessed these arms. But he said the amount of weapons has grown substantially. One beneficiary, he said, is Islamic Jihad, a smaller armed group that sometimes rivals Hamas. Islamic Jihad was responsible for most of the latest wave of fighting against Israel.
"Hamas has more of everything and good stuff, but the Jihad . . . got stronger by far, not stronger than Hamas, but it's a very strong organization now," he said.
Abu Ahmad, spokesman for Islamic Jihad's military wing, confirmed that his group had beefed up its capabilities, including the new use of mobile rocket-launchers.