An Israeli Border Police officer was seriously wounded Saturday during violent riots that erupted along Israel's border with the Gaza Strip.
Two Palestinians, including a 13-year-old boy, were also seriously injured in the cross-border fire that wounded 39 other Palestinians, officials said.
The violence broke out during a Gaza protest organized by the enclave's Islamist rulers Hamas and other factions allegedly in support of Jerusalem, where Palestinian clashes with Israeli police helped spark an 11-day Israel-Hamas conflict in May.
Hundreds of Palestinians gathered in the heavily fortified border area, where some tried to scale the border fence and others threw explosives towards Israeli troops, the Israeli military said.
"IDF (Israeli military) troops responded with riot dispersal means, including when necessary live fire," it said in a statement.
Gaza's health ministry said a 13-year-old boy was in critical condition after being shot in the head. It described most of the other injuries as moderate, including gun shots to limbs, backs and abdomens.
Cross-border fire from Gaza critically wounded an Israeli undercover border police soldier, who is in hospital receiving medical treatment, the military said. He is said to be suffering from a severe head injury and has been taken for an urgent operation upon arriving at Soroka Medical Center in Be'er Sheva.
There was no claim of responsibility for the Gaza gunfire.
The border incidents come days after Israel announced a resumption of Qatari aid to Gaza, a move seen as bolstering an Egyptian-mediated truce to the May fighting.
Several Palestinian leaders gave speeches near the protest site, where they called on Israel to lift restrictions Gaza, Palestinian media reported.
Israel keeps Gaza under a blockade, tightly restricting movement out of the territory that is home to 2 million Palestinians. Egypt also maintains restrictions on the enclave. Both cite threats from Hamas for the restrictions.