Organisers of a Gaza-bound aid flotilla have suggested that Israel was behind a drone strike that targeted one of its vessels in Tunisian waters in the early hours of Tuesday.
The boat is one of dozens in the Global Sumud Flotilla that plans to sail more than 2,000 kilometres to the besieged enclave in a bid to break Israel's siege, which has left hundreds of thousands of Palestinians on the brink of starvation.
The vessel, known as the 'Family Boat', was moored off the coast of Sidi Bou Said and was carrying members of the organisation's steering committee. None of the six crew members on board were harmed in the attack.
Security camera footage shared by the organisation shows a flash of light falling from the sky onto the vessel, causing it to go up in flames.
A humming sound characteristic of a drone can be heard in the video.
The flotilla said passengers extinguished the fire, though damage was caused to the deck.
One of the crew members told reporters on Tuesday that he saw a drone three or four metres above his head before it struck the boat.
"This was a shameful attack," he said at a press conference in Tunis.
Tunisian authorities earlier called suggestions that a drone had caused the fire "completely unfounded" and claimed that it had been caused by a cigarette or a lighter.
"What happened last night showed who we are dealing with," Freedom Flotilla activist Thiago Avila told reporters.
"Who has [an] interest in stopping humanitarian aid [from] getting to starving children in Gaza? Who has been assassinating health workers, United Nations workers, civil defence workers, journalists? Who has been committing all these war crimes?" he said.
Francesca Albanese, UN special rapporteur for the occupied Palestinian territories, shared the footage on social media and highlighted the sound and explosion.
"Draw your own conclusions," she wrote.
The human rights expert is currently in Tunisia with the organisers ahead of their departure.
Dozens of boats have joined the flotilla in a bid to break Israel's 18-year blockade on Gaza. Hundreds of activists from more than 40 countries are participating in the effort.
Among them is climate activist Greta Thunberg, who was on board the first boat – the Madleen - to try and reach Gaza in June.
"Acts of aggression aimed at intimidating and derailing our mission will not deter us", the organisation said in a statement in the wake of the attack.
This is the third attempt to break Israel's siege this year. Two attempts made in June and July by Madleen and Handala were intercepted by Israeli forces, who detained and deported the activists.
Israel has heavily restricted food and aid from entering Gaza for almost two years, triggering a famine across the entire territory and causing critical shortages of medical supplies and baby formula.