Hezbollah's leader vowed Thursday to retaliate against Israeli interests anywhere in the world for the assassination of Imad Mughniyeh, one of the militant group's most notorious operatives, warning of a war without boundaries in a eulogy delivered to throngs of fist-waving mourners.

Israel ordered its military and embassies overseas to go on alert earlier in the day and recommended Jewish institutions around the world do the same, fearing revenge attacks for the car bomb that killed Mughniyeh Tuesday night in Damascus.

...The fiery speech by Hezbollah chief Hassan Nasrallah at Mughniyeh's funeral signaled that the Iranian-backed Shiite guerrilla group was ending a policy it has proclaimed for years of battling Israel only on Israeli or Lebanese territory, raising the specter of attacks in Western or other countries.

...Hezbollah and its Iranian backers blamed Israel for killing Mughniyeh, but Israel denied involvement. In a videotaped eulogy broadcast on a giant screen to thousands attending the south Beirut funeral, Nasrallah said Israel had taken the fight outside the 'natural battlefield' of Israel and Lebanon.

'You have crossed the borders,' said Nasrallah, himself in hiding because of fears of assassination since the summer 2006 war between Israel and Hezbollah. 'With this murder, its timing, location and method — Zionists, if you want this kind of open war, let the whole world listen: Let this war be open.'

The thousands of black-clad mourners in the ceremony hall raised their fists in the air, chanting, 'At your orders, Nasrallah.'

...Unlike many Middle Eastern leaders whose speeches are riddled with idle threats, Nasrallah is known for delivering on his promises.

...Nasrallah warned Israel that its alleged killing of Mughniyeh was a 'very big folly' which will be avenged.

'Mughniyeh's blood will lead to the elimination of Israel. These words are not an emotional reaction,' he said.

Iranian Foreign Minister Manouchehr Mottaki, who came to the funeral in Lebanon, offered condolences to the family and Mughniyeh's associates, before accepting condolences himself. Underlining Iran's close ties to Hezbollah, he sat between Mughniyeh's father and Hezbollah's deputy leader.

'He's not the first martyr, nor will he be the last on this path,' Mottaki said, reading a statement of condolences from Iranian President Mahmoud Ahmadinejad with an interpreter translating into Arabic. 'There will be hundreds and millions more' like him.

Afterward, the coffin was carried outside through the crowds of mourners, who marched with it to a nearby cemetery, praying aloud, as some chanted 'Death to Israel' and 'Death to America.'