The threats appeared to be tied to the third anniversary of the death of a former Hezbollah commander, Imad Mughniyeh, who died in a mysterious explosion in Syria. Hezbollah blames Israel and has repeatedly vowed revenge.
The Israeli Foreign Ministry refused to discuss the nature of the threats, referring only to "extraordinary events." On Friday, Israel's National Security Council warned Israeli and Jewish travelers that they could be targets in Turkey, Egypt, Georgia, Venezuela, Armenia, the Ivory Coast, Mali and Mauritania. It advised travelers to stay away from any areas where Israelis might congregate.
Officials would not say which diplomatic missions were closed, but they said they were located in nations listed in the travel warning.
"There is a threat directed against Israeli targets," said Foreign Ministry spokesman Yossi Levi, who added that Israeli authorities in Israel and abroad were working closely "to tackle the recent situations."
The Israeli government issued a similar warning last year before the second anniversary of Mughniyeh's death in a Feb. 12, 2008, car bombing in Damascus.
Both Hezbollah's leader, Hassan Nasrallah, and its backers in Iran accused Israel of assassinating Mughniyeh, a senior Hezbollah operative implicated in attacks against Americans and Israelis. Israel denied involvement.
Nasrallah has vowed revenge. "We will choose the time, place and manner of punishment," he said a month after the killing.
Around the same time, the New York City Police Department beefed up protection of synagogues, fearing Hezbollah might target Jews outside of Israel.
Israel and Hezbollah fought a monthlong war in 2006.