"A soldier and his brother were killed in an Israeli strike that targeted them in the town of Khirbet Selm in Bint Jbeil (district) while they were travelling on a motorbike" heading home from the soldier's post, the army statement said.

The raid comes one day after 11 people including three civil defence personnel were killed in strikes in the country's south, according to updated health ministry figures, while two army troops were also wounded.

Prime Minister Nawaf Salam has called the strike that killed the civil defence workers a "war crime".

President Joseph Aoun said Wednesday that authorities were keeping up "contacts to consolidate the ceasefire and stop the demolition of homes in occupied southern villages", according to a statement from his office.

A 10-day truce that began on April 17 and was extended for three weeks was supposed to pause a month and a half of war between Israel and Iran-backed militant group Hezbollah during which Israeli troops invaded south Lebanon.

Under the truce, Israel reserves the right to act against "planned, imminent or ongoing attacks".

Its troops are operating inside an Israeli-announced "yellow line", which demarcates a ribbon of Lebanese territory around 10 kilometres (six miles) deep along the length of the border, where Lebanese have been warned not to return.

Lebanon's state-run National News Agency (NNA) reported Israeli airstrikes on around a dozen locations in south Lebanon on Wednesday and said Israeli troops were also blowing up homes in at least two locations.

The health ministry said a strike on Jibsheet a day earlier killed five people, including two women. The NNA said they were all members of the same family.

Israeli strikes in Lebanon have killed at least 53 people since the ceasefire began less than two weeks ago, according to an AFP tally of health ministry and army statements.

Hezbollah lawmaker Hassan Fadlallah vowed Wednesday that Israeli attempts to "establish a security belt on our land... will be brought down by the sacrifices of the resistance and the steadfastness of our people", reiterating his party's rejection of direct talks with Israel.

Hezbollah drew Lebanon into the Middle East war on March 2 by firing rockets towards Israel to avenge the US-Israeli killing of Iranian supreme leader Ali Khamenei.

Since the ceasefire, the group has been claiming attacks on Israeli targets, saying its fighters are acting in response to Israeli ceasefire violations.