Iran unveiled an unmanned bomber jet Sunday that will probably fail to tip the region’s strategic balance but suggests Tehran continues to invest in shoring up its conventional weapons capabilities.

President Mahmoud Ahmadinejad, speaking during annual Defense Industry Day ceremonies, described the Karrar drone as “a messenger of honor and human generosity” before also terming it a “messenger of death for the enemies of humanity.”

The audience applauded and praised the prophet Muhammad and his descendants as a sheet covering the olive-green aircraft was removed. A short video showed what was said to be the drone launching into the sky and firing a missile as martial music played.

Ahmadinejad, standing on a stage with Defense Minister Ahmad Vahidi and others in military uniform, said the bomber was meant as a deterrent against potential attacks. “The key message is to prevent any clashes that cause killings,” he said. “We must make efforts to render useless all weapons of the enemy with our defense potential.”

Brig. Gen. Mohammad Alizadeh, managing director of Iran’s Aircraft Manufacturing Industries Co., told state television that the computer-operated Karrar could be adjusted to ranges of up to 180 miles. He said it could carry bombs of varying sizes and ranges that could strike at ships, communications installations, airports, bases and bridges.

Other reports on state TV said the drone has a range of 620 miles. Either distance is not enough to reach Israel, but more than enough to conduct surveillance over or launch strikes against U.S. ships and bases in the Persian Gulf, Iraq and Afghanistan.

Iran typically announces new military or scientific achievements during annual commemorations marking its army, defense industry or nuclear program. The Karrar unveiling came a day after Russian and Iranian technicians began turning on Iran’s first nuclear power reactor and amid Tehran’s ongoing tensions with the U.S. and its allies over its nuclear program.

Few military experts take Iran’s boasts about its conventional military program seriously. Iran spends a little more than $10 billion on its military a year, less than Israel and a fraction of America’s military budget. By Western standards, its forces performed miserably during the 1980-1988 Iran- Iraq war.

But most defense analysts say that in case of a military confrontation Iran could more successfully employ guerilla attacks by proxy forces to inflict mass casualties or draw the U.S. into a larger and draining conflict. Ahmadinejad said Sunday that if Israel ever attacked Iran, “the span of our reaction would be the entire planet Earth.”

But the Karrar drone may serve more as a palliative to ease fears and boost the morale of Iranian citizens and military personnel worried about the increased talk of possible U.S. or Israeli airstrikes on Iran’s nuclear sites. Iranian officials regularly dismiss the war talk coming from the U.S. and Israel as psychological warfare meant to pressure the Islamic Republic. One reporter covering the ceremony for state television cheerily boasted that Iran had “broken the monopoly of America” and other countries on manufacturing unmanned attack planes.

The drone has been in the works for seven or eight years, Alizadeh said, and won’t “disturb the regional balance” until mass production is carried out successfully. At one point about three years ago, supreme leader Ayatollah Ali Khamenei visited the plant where it was being built, he said.

“I asked the leader to do a favor and pray for the drone,” Alizadeh said. “He stroked the head of the drone and said a prayer. Believe me, after that prayer, we all got a special energy.”

daragahi@latimes.com