JERUSALEM -- An Israeli-Palestinian smuggling ring funneled iron, electronic equipment and other prohibited materials to Gaza, bypassing Israel's stringent border security to help Hamas rebuild its militant infrastructure following last year's war, Israel said Monday.

Hamas, a bitter enemy of Israel's, suffered heavy losses in last year's 50-day war, in which Israel carried out some 5,000 airstrikes on targets throughout Gaza. Hamas fired thousands of rockets into Israel during the fighting, in which more than 2,200 Palestinians and 72 people on the Israeli side were killed.

Hamas, which has controlled Gaza since 2007 but is suffering from international isolation and a cash crunch, has been trying to rebuild itself since the fighting ended.

Israel has charged nine people in the ring, among them three Jewish Israelis who own companies that sell the materials, with assisting an enemy in wartime, terror financing and fraud, among others. The remaining accused are Palestinians from Gaza.

Israel's internal security agency said the materials were smuggled on trucks through Kerem Shalom, the main cargo crossing between Israel and Gaza. The materials were listed as destined for straw companies and were hidden among other goods which are permitted to enter Gaza. It said the goods were delivered through Palestinian middle men.

"In this way, large amounts of materials bought in Israel and smuggled to the Gaza Strip systematically and over time made their way to Hamas' military infrastructure," the Shin Bet said in a statement.

The agency said at least $375,000 was paid to the Israeli players.

Zion Amir, a lawyer for one of the Israelis, whose name wasn't made public, said his client denied the charges. There was no immediate reaction from the other defendants or Hamas.

Israel considers Hamas a terrorist group, and cases of Jewish Israelis collaborating with the group are extremely rare.