A spokesperson for the Lebanese Civil Defence, a state-run rescue force, told Reuters the three rescuers were initially trapped under rubble by the second Israeli strike on the town of Majdal Zoun and were later confirmed dead.
Lebanese President Joseph Aoun's office posted on social media that the three men were carrying out a rescue and first aid mission in the town.
The Lebanese army said earlier that two troops were also wounded in the second Israeli strike.
The Israeli military did not immediately respond to a request for comment.
Lebanese Prime Minister Nawaf Salam condemned the strikes as "a new and blatant war crime committed by Israel."
The United Nations Human Rights office said last month that Israeli air strikes on civilians including healthcare workers in Lebanon may amount to war crimes.
More than 2,500 people have been killed in Israeli strikes across Lebanon since March 2, when Iran-backed militant group Hezbollah fired on Israeli positions and triggered a widespread Israeli air and ground campaign. The toll includes more than 100 medics, as well as over 270 women and more than 170 children.
The US-mediated ceasefire agreed between Israel and Lebanon has led to a reduction in hostilities, but Israel and Hezbollah have continued to clash in southern Lebanon, accusing each other of violating the ceasefire.
Israeli troops are occupying a strip of southern Lebanon and have warned people not to return to their homes there, but the Israeli air force has also continued strikes outside that strip.
Last week, Israeli strikes killed a Lebanese journalist in southern Lebanon, with Lebanese authorities and press advocates saying continuing Israeli attacks had blocked rescuers from accessing the site where the journalist had been trapped under the rubble.
Hezbollah, meanwhile, has kept up its drone and rocket attacks against Israeli troops in Lebanon and on northern Israel.
Earlier on Tuesday, the Israeli military said it had found and dismantled tunnels in southern Lebanon used by Hezbollah.
with DPA
