Israel has declined to comment.
Iran said on Saturday it expects Lebanon's Tehran-backed Hezbollah group to hit deeper inside Israel and no longer be confined to military targets after Israel killed the Hezbollah military commander.
Hezbollah has been exchanging near-daily fire with Israeli forces, saying it is targeting military positions over the border, since its Palestinian ally Hamas attacked Israel on October 7, sparking war in Gaza.
But a strike claimed by Israel in an overcrowded residential area of South Beirut changed the calculus, Iran's mission to the United Nations said.
"We expect... Hezbollah to choose more targets and (strike) deeper in its response," said the mission quoted by the official IRNA news agency.
"Secondly, that it will not limit its response to military targets."
The strike on Tuesday killed Hezbollah commander Fuad Shukr. According to Lebanon's health ministry, five civilians -- three women and two children -- also died.
Israel said Shukr was responsible for rocket fire that killed 12 youths in the annexed Golan Heights, and had directed Hezbollah's attacks on Israel since the Gaza war began.
"Hezbollah and the (Israeli) regime had observed certain lines", including limiting strikes to border areas and military targets, Iran's mission said.
The Beirut strike crossed that line, it added.
Hours after Shukr's killing, the political leader of Hamas, Ismail Haniyeh, was killed in a pre-dawn "hit" on his accommodation in Tehran, Iran's Revolutionary Guards said.
Israel has declined to comment.
On Thursday, Hezbollah chief Hassan Nasrallah said Israel and "those who are behind it must await our inevitable response" to the killings of both Shukr and Haniyeh.
Iran and Hamas have also vowed to retaliate.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)