Hezbollah has the right to acquire air-defence weapons and to use them against Israeli warplanes that violate Lebanese air space on a daily basis, the leader of the Iranian-backed group said on Monday.

The remarks by Sayyed Hassan Nasrallah were the first clear sign that the group might have already obtained such a system that could inflame tensions with Israel 2-1/2 years after the enemies fought a 34-day war.

"Every few days there is (an Israeli media) report that the resistance has obtained advanced air-defence weapons, of course I don't deny or confirm this," Nasrallah told a rally to commemorate the first anniversary of the assassination of the group's military commander Imad Moughniyeh.

"What I want to confirm today is that we have every right to obtain any weapon, including air-defence weapons, and we have every right to use this weapon," he said.

Nasrallah said obtaining such a system would tip the balance in any conflict with Israel because the Jewish state relies heavily on air supremacy in its military planning.

Nasrallah has been more open about his group's military capabilities since the 2006 war as part of a deterrence strategy.

The group managed to replenish its arsenal and increase the size of its military wing in the months following the 2006 war despite a U.N. Security Council resolution banning any arms shipments to the group.

Israel has conducted daily overflights of Lebanon, also in breach of the U.N. resolution, arguing that it needs to monitor Hezbollah's rearming and military movements.

Nasrallah reiterated that he stands by a vow to avenge the Feb. 12, 2008 killing of Moughniyeh in Damascus, which the group accused Israel of carrying out.

"This promise will be fulfilled, God willing...," he said, adding that he would say no more on the matter.

Israel has never confirmed it was behind the car bomb attack, although it welcomed the death of a man who had been on the United States' most wanted list for 25 years.

Moughniyeh had been blamed for a wave of Western hostage-taking in Beirut in the 1980s and deadly attacks on U.S. and Israeli targets in Lebanon and beyond.