DUBAI (Reuters) - Iran said on Sunday the launch of a drone aircraft into Israel by Iranian-backed Lebanese militant group Hezbollah was a sign of the Islamic Republic's military capabilities.

Hezbollah claimed responsibility on Thursday for the launch of the drone aircraft which Israel shot down last weekend after flying 25 miles into the Jewish state, saying the drone's parts were manufactured in Iran and assembled in Lebanon.

Tensions have increased in the region with Israel threatening to bomb the nuclear sites of Hezbollah's patron Iran if diplomacy and sanctions fail to stop Iranian nuclear activity the West suspects is meant to develop a weapons capability. Tehran says it is seeking only civilian nuclear energy.

Iran has threatened in turn to attack U.S. military bases in the Middle East and retaliate against Israel if attacked.

"Iran has great capabilities and our capabilities are at the service of the Islamic nation," Defence Minister Ahmad Vahidi told state television. "The Zionist regime (Israel)...was defeated in this respect and it can no longer bully Islamic nations," he added.

Vahidi said Iran believed Hezbollah had the right to launch the drone into Israeli airspace since Israel's warplanes "repeatedly violate Lebanese airspace".

Iran has said the incursion exposed the weakness of Israeli air defence, indicating that Israel's Iron Dome anti-missile defence system "does not work and lacks the necessary capacity". The Iron Dome system, jointly funded with Washington, is designed to down short-range guerrilla rockets, not slow-flying aircraft.

Hezbollah, a powerful Shi'ite Muslim militant and political group backed by Syria and Iran, was established with the help of Iran's Revolutionary Guards after Israel's 1982 invasion of Lebanon.

Hezbollah last fought Israel in 2006 during a 34-day war in which 1,200 people in Lebanon, mostly civilians, and 160 Israelis, mostly soldiers, were killed.

(Reporting by Zahra Hosseinian, editing by Diana Abdallah)