Iranian officials were quoted in their state media as saying that the drone’s ability to enter Israeli airspace exposed the weakness of Israel’s air defenses.

Since the drone’s downing, Israel has deployed a missile-defense system near the Lebanese border. An army spokesman confirmed that the Patriot missile-defense system was deployed near the northern Israeli city of Haifa. The system, which was developed with American backing, can intercept medium-range ballistic missiles, planes and drones from a distance of 35 to 100 miles.

“There is a sense of potential with Hezbollah . . . as well as with Iran, for things to heat up quickly. There is a sense of tit-for-tat,” said the Israeli military official.

Iran has accused Israel of assassinating scientists involved in its nuclear facilities and of sabotaging Iran’s online systems with complex virus and cyber-hacking. A computer worm known as Stuxnet that was designed by the United States and Israel to disable controls on sensitive equipment is credited with setting back the Iranian nuclear program several years.

Iran, in turn, has been accused of launching attacks on Israeli computer systems and other “Western targets.”

On Thursday, U.S. Defense Secretary Leon Panetta revealed in a speech on cyber security that computer attacks over the summer had devastated the computer systems of oil companies in Saudi Arabia and Qatar.

Speaking to a group called Business Executives for National Security in New York City, Panetta described the Shamoon virus that infected the computer systems as “very sophisticated.” He said it first struck the Saudi Arabian state oil company Aramco two months ago, causing the computers to display an image of a burning American flag. Then the virus overwrote all of the files in a computer with what Panetta called “additional garbage data” that rendered the computers useless. Panetta said 30,000 computers had been destroyed.

A few days later, Panetta said, the virus appeared on computers of a Qatari energy company, RasGas.

Panetta did not blame the attacks on Iran, but both Saudi Arabia and Qatar are bitter foes of Iran. The two countries also have been providing weapons to insurgents fighting to topple the regime of Syrian President Bashar Assad, an Iranian ally.