A Hezbollah supporter in Beirut holds a portrait of late Hezbollah military commander Imad Mughniyah at a ceremony in 2013 to mark the death of Hezbollah leaders. (Bilal Hussein/AP)

The revelation that the CIA cooperated with Israel’s Mossad spy agency in the assassination of a top Hezbollah military commander in 2008 is poised to intensify a shadow war with the militant Lebanese group that could involve retaliation against U.S. interests around the world, analysts said.

In an exclusive story published online Friday night, The Washington Post reported that the U.S. intelligence agency coordinated with Mossad in carrying out a February 2008 car bombing in the Syrian capital, Damascus, that killed Imad Mughniyah.

The militant commander was implicated in killing hundreds of Americans in attacks that included the U.S. Embassy bombing in Beirut in 1983 and assaults on American forces in Iraq by Iranian-backed militias, according to the Post’s report, which cited multiple former U.S. officials. The killing of Mughniyah, a key figure behind attacks on scores of Israelis, was approved by officials in the George W. Bush administration, according to the report.

The report said the operation required extensive planning and cooperation between the two agencies. One of official is quoted as saying that operatives detonated some 25 practice bombs at a CIA facility in North Carolina “to make sure we got it right,” killing Mughniyah while avoiding civilian causalities. The real bomb was triggered remotely in Tel Aviv by Mossad agents, according to the report, but CIA operatives in Damascus acted as spotters and could have called off the attack.

Samar Hajj, a Lebanese analyst who is close to Hezbollah, said the report reinforced the impression — true or not — among officials in the Iranian-backed group that covert Israeli operations are signed off in Washington. She said that disclosures in the report would add urgency to desired Hezbollah attacks against Israel, after both sides exchanged fire Wednesday in a flare-up that triggered fears of war.

Seven years after the death of Hezbollah's Imad Mughniyah, The Post's Adam Goldman and the Washington Institute's Matthew Levitt look at the international cooperation that brought down the former military commander. (Davin Coburn, Randolph Smith and Kyle Barss/The Washington Post)

“We do not differentiate between CIA and Mossad. They are the two faces of the same coin,” Hajj said. She added that Hezbollah probably was aware of U.S. involvement in Mughniyah’s killing, which the Lebanese group had blamed on the Mossad.

She said Hezbollah was prepared to attack Israel at points around the world, which was hinted at during a speech by the group’s leader, Hasan Nasrallah, given Friday before the Post’s story was published.

“There will be more retaliation operations,” Hajj said.

During his speech, Nasrallah issued a tough warning to Israel, saying that Hezbollah would not hesitate to strike. He indicated that an attack on Wednesday – which involved an anti-tank missile fired at Israeli soldiers, killing two – was retaliation for an air assault in southern Syria on Jan. 18 that killed an Iranian commander and six Hezbollah fighters. One of those killed the Jan. 18 attack was the son of Mughniyah, Jihad.

“We are not afraid of war. We will fight this war. We will achieve victory, God willing,” Nasrallah said, while threatening to expand the traditional areas of conflict between Israel and Hezbollah beyond Lebanon.

Israeli officials have been alarmed by what they say is a build up of Hezbollah’s military presence along the border area. The group possesses a massive arsenal of rockets that can be fired at Israel cities, and its fighters are widely believed to have plans to carry out incursions in Israeli border communities in the event of a war.

The two fought a devastating war in 2006, and Hezbollah’s military capabilities have expanded dramatically since then, according to analyst and Israeli officials.

Yossi Melman, an Israeli journalist who has written extensively on espionage issues, said that Hezbollah would likely “try to settle this score with the U.S.,” although he did not expect an immediate response from the group over the report.

He added that the CIA and Mossad could have assistance in the assassination plot from Jordanian intelligence, speculating that the bomb “was smuggled via Jordan into Syria.”

Jordanian officials could not be reached for comment, and neither officials in Hezbollah nor Israel would comment on the Post’s report.

Imad Salamey, a politics professor at the Lebanese American University, said the disclosures add pressure to Hezbollah. The group probably wants to respond, but the news comes at a sensitive time: Its patron, Iran, is engaged in negotiations with the United States and other world powers over the Islamic Republic’s nuclear program.

“Your leadership has been targeted by the United States, so what do you do? Hezbollah is being cornered by this information,” he said.

There are questions about the timing of the disclosures, released seven years after the assassination.

Talal Atrissi, an analyst who is close to Hezbollah, said that the disclosure could be interpreted by Hezbollah and Iran as an attempt by former and current U.S. officials as an attempt to scuttle the nuclear talks. The United States and its allies in Europe and the Arab world, as well as Israel, think the program is intended to build nuclear weapons, but Iran denies this.

“The leak is meant to undermine the talks, and that benefits Israel because it opposes these negotiations,” he said.

Still, he and other analysts did not think that the disclosures would derail the nuclear talks, which has had its deadline extended twice over a failure to reach an accord.

“Iran believes the bilateral talks on the nuclear file are more important than a story from the past, especially since Hezbollah has changed its methods and focus, becoming now different than it was in the 80s,” Atrissi said.

He was referring to attacks against the U.S. Embassy, among others, by Hezbollah that earned it a notorious reputation in the United States, which along with the European Union classifies the group as a terrorist organization.

Mughniyah is described in the report as involved in those and other attacks, including the bombing of the Israeli Embassy in Argentina in 1992 as well as a Jewish community center in the same country two years later. The latter attack killed 85 people.

In coordination with Iran, he also was involved in organizing Shiite militias in Iraq to carry out scores of attacks on U.S. forces after the 2003 invasion, the report said. Those attacks persuaded the Bush administration to approve the assassination, the report said.

Johnny Mounayar, a writer and political commentator in Lebanon, said that the report’s publication undoubtedly has forced Iranian and Hezbollah officials to discuss a response.

Suzan Haidamous in Beirut and Ruth Eglash in Jerusalem contributed to this report.