Under a truce that ended a recent war between Israel and Iran-backed Hezbollah, the army has been deploying in south Lebanon and dismantling the militant group's infrastructure there.

The deaths come as Lebanon tackles the thorny issue of disarming Hezbollah, with the cabinet this week tasking the army with developing a plan to do so by year end and the Iran-backed group pushing back.

Iran said Saturday it opposed the Lebanese government's decision.

An army statement gave a preliminary toll of six soldiers killed and others wounded "while an army unit was inspecting a weapons depot and dismantling its contents in Wadi Zibqin", in the Tyre district near the Israeli border.

Investigations were underway to determine the cause of the blast, it added.

A military source, requesting anonymity as they were not authorised to brief the media, told AFP the blast took place "inside a Hezbollah military facility".

Troops were "removing munitions and unexploded ordnance left over from the recent war" between Israel and Hezbollah when the blast occurred, the source added.

President Joseph Aoun said he was informed by army commander Rodolphe Haykal of the "painful incident" that led to troop casualties.

Prime Minister Nawaf Salam paid tribute on X to the troops who were killed "while performing their national duty", calling the army the protector of Lebanon's "unity and its legitimate institutions".

- Disarmament push -

The blast came days after Andrea Tenenti, spokesperson for UN peacekeepers in Lebanon, said that troops had "discovered a vast network of fortified tunnels" in the same area.

Under the November ceasefire which sought to end more than a year of hostilities between Israel and Hezbollah, weapons in Lebanon should be restricted to state institutions.

The government has tasked the army with presenting a plan for restricting weapons to government forces by the end of August.

Lebanon's cabinet met twice this week on the issue, while Hezbollah has rejected the government's decision to take away its weapons.

A senior adviser to supreme leader Ayatollah Khamenei said Saturday that Iran "is certainly opposed to the disarmament of Hezbollah... Iran has always supported the people and the resistance of Lebanon and continues to do so."

Lebanon's cabinet on Thursday discussed a US proposal that includes a timetable for Hezbollah's disarmament, with Washington pressing Beirut to take action.

The government endorsed the introduction of the US text without discussing specific timelines, and called for the deployment of Lebanese troops in border areas.

It also called for the withdrawal of Israeli troops from five south Lebanon areas they have occupied since the recent war.

In April, Lebanon's military said three troops were killed in a munitions blast in the south, just days after a soldier was killed and three others wounded in another explosion as authorities said they had been dismantling mines in a tunnel.