An electrical short circuit in a store containing oxygen supplies for Covid patients caused the blast that rocked a Palestinian refugee camp in south Lebanon, the Islamist group Hamas said Saturday.

One man died of his injuries in Friday night's explosion that left a few people wounded, said a Palestinian official in the Burj al-Shemali camp, outside the port city of Tyre.

Hamas, the Palestinian Islamist movement, denied media reports that an arms depot had blown up.

The explosion, which blackened the walls and shattered windows of a nearby mosque, was caused by an electrical short circuit that sparked a fire in a store containing the oxygen tanks, it said in a statement.

"An electrical short circuit in a storage depot containing a quantity of gas and oxygen canisters for coronavirus patients" caused the blast, it said.

"The fire caused damage to property but the impact was limited," it said, without detailing casualties.

Officially, Lebanon hosts some 192,000 Palestinian refugees, most of whom live in the country's 12 camps, according to the United Nations Relief and Works Agency (UNRWA).

By longstanding agreement, the Lebanese army does not enter the camps, leaving security inside to Palestinian factions.