Four Israeli embassies have been asked to shut down and diplomats advised to remain in their homes following threats stemming from the third anniversary marking the death of Hezbollah leader Imad Mughniyeh, killed in a Damascus car bomb in February 2008.
Hezbollah blamed Israel for his death.
A statement released by the foreign ministry Tuesday said a number of "irregular incidents" have been noticed recently around a number of Israeli diplomatic missions abroad.
"At this point we think there is a threat against those locations, and it is being dealt with," the statement said.
The ministry did not identify the embassies in question. The four embassies did not open as usual on Monday.
Friday, the National Security Council's counter-terrorism bureau noted that the warning against Israeli and Jewish targets abroad had increased. It referred to eight countries including Egypt, Turkey, Georgia, Armenia, the Ivory Coast, Mali, Mauritania and Venezuela.