Hezbollah accused Israel Friday of trying to start a war with the militant Islamic group by assassinating a top commander, and warned that the Jewish state's "disappearance" is an inevitable fact.

Hezbollah leader Hassan Nasrallah said last week's killing of Imad Mughniyeh in a car bombing in Syria was a "pre-emptive" strike meant to set the stage for more assassinations of the Lebanon-based group's top officials.

"The Israelis are definitely threatening a war," Nasrallah told tens of thousands gathered Friday in southern Beirut for a memorial for Mughniyeh and two other Hezbollah leaders killed in the 1980s and 1990s.

"The disappearance of Israel is an inevitable fact. It is an historical process in the region which will come to an end in several years," he told the Jerusalem Post.

Israel has denied involvement in the Feb. 12 car bombing. But Nasrallah said Hezbollah's investigation into the killing has "increased our conviction of Israeli responsibility."

Nasrallah repeated earlier threats to retaliate for Mughniyeh's death, and also said Hezbollah would strike Israel with dozens of rockets if it attacked the guerrilla group in Lebanon as it did in 2006. Hezbollah is "ready for a confrontation," he said.

"We will not allow the enemy to persist in killing our commanders. We will choose the place and time to retaliate," Nasrallah said by video link to his supporters, who responded with cheers and bursts of gunfire.

Israel's "army and its tanks will be destroyed in the south, and Israel will be without an army and then it will be no more," he said.

Nasrallah threatened Israel after last week's bombing with an "open war," sparking criticism and fears at home and abroad. Saudi Arabia and Kuwait issued travel advisories to their citizens in Lebanon, and two French cultural centers were closed in the country this week.

Hezbollah's leader assured foreigners in Lebanon, however, that they were not a target. "Our enemy is Israel, and our revenge is against Israel," he said.

Israel already increased security at Israeli diplomatic offices and Jewish institutions abroad.

It also ordered all incoming airline passengers to be seated half an hour before landing -- to give flight crews more time to spot suspicious passengers and to make it harder for hijackers to take over a plane, Transport Ministry spokeswoman Ora Salomon said Friday.

"The directive to all airlines is to be more alert and more careful," Salomon said.

Mughniyeh gained notoriety during Lebanon's civil war in the 1980s for attacks on American interests and for kidnapping foreigners in Lebanon.

Nasrallah disclosed Friday that Mughniyeh also led a 2000 operation on the border with Israel that resulted in the capture of two Israeli soldiers. The soldiers were killed in the attack, and their bodies were later exchanged for Lebanese and Arab guerrillas held by Israel.

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The Associated Press contributed to this report.