Within hours of the explosion, Israel offered to provide its old foe, Lebanon, with humanitarian aid. It was not clear the help would be welcomed.
The approach was made through foreign mediators, since Israel and Lebanon have no diplomatic relations. It came just over a week after Israel said it had repelled an infiltration attempt by a Hezbollah squad along its northern frontier, in part by firing artillery shells into southern Lebanon.
Israel invaded Lebanon 2006, attempting to uproot Hezbollah, the Shiite militia and political party. They fought a devastating, monthlong war, and violence on a smaller scale has flared repeatedly since then. Hezbollah is now part of Lebanon’s governing coalition.
No Lebanese politician would want to be seen as allied with or beholden to Israel, which remains deeply unpopular across Lebanon’s political spectrum.
Israel’s defense minister, Benny Gantz, and foreign minister, Gabi Ashkenazi, both former army chiefs of staff, offered medical assistance via “international defense and diplomatic channels,” Mr. Gantz said on Tuesday on Twitter.
Prime Minister Benjamin Netanyahu said he had instructed a top adviser to speak with a United Nations envoy about how to deliver aid. On Wednesday, in Parliament, he said, “we are ready to offer humanitarian assistance, as human beings to human beings.” He conveyed the same message in Arabic on Twitter.
An official in Israel’s Ministry of Defense, speaking on the condition of anonymity because of the diplomatic sensitivity, said there had been no reply from Lebanon by Wednesday evening. But another government official said contacts were underway between Israel and Nikolay Mladenov, the United Nations special coordinator for the Middle East peace process. Mr. Mladenov’s office did not immediately respond to a request for comment. Asked later about possible Israeli aid to Lebanon, a United Nations spokesman, Farhan Haq, said: “Obviously we appreciate all offers of assistance from member states.”