JERUSALEM – Israel will deploy tanks equipped with a new defense system along the Gaza border after Palestinian militants for the first time used a sophisticated, tank-piercing missile believed to be the most advanced weapon in their arsenal.

Israeli defense officials said the laser-guided Kornet came from Iran, the top backer of Gaza’s Hamas rulers. Lebanon’s Shiite Hezbollah guerrillas, also backed by Iran, used the Russian-made Kornets in their 2006 war against Israel, destroying or damaging several dozen Israeli tanks.

The Palestinian use of Kornet missiles, confirmed by Israel’s military chief on Tuesday, marks a new milestone for Gaza militants, who have steadily built up their arsenal from a collection of crude, homemade rockets to include more menacing imported weapons.

Israel’s answer is called Trophy, a first-of-its-kind Israeli-made system carried by tanks that is designed to shoot down missiles like the Kornet. The system, mounted on the side of a tank, detects an incoming missile and fires a projectile at it, destroying it, according to video of a test provided by the developer.

Violence has been escalating along the Gaza border in recent weeks. In his parliamentary testimony Tuesday, Israel’s military chief, Lt. Gen. Gabi Ashkenazi, confirmed militants fired a Kornet missile for the first time earlier this month, and it penetrated an Israeli tank.

He called the missile “one of the most dangerous in the battlefield.” Ashkenazi said. He said the missile did not explode inside the tank, and no one was hurt.

The Israeli defense officials, speaking on condition of anonymity because they were not authorized to discuss such matters publicly, provided no proof to support their claim that the missile came from Iran.