Tunisian authorities have denied claims that one of the Gaza-bound vessels carrying aid and pro-Palestinian activists including Greta Thunberg was attacked by a drone.

The organisers of the flotilla, Global Sumud Flotilla (GSF), said that the Portuguese-flagged vessel had been struck by a drone while anchored outside the port of Sidi Bou Said in Tunisia. All six passengers and crew were safe, they added.

A spokesperson for Tunisia's national guard told the Agence France-Presse news agency that 'no drone' had been detected and the investigation was ongoing.

The humanitarian aid flotilla set sail from Barcelona last week and arrived in Tunisia on Sunday.

The GSF said their 'Family boat' was struck in Tunisian waters, and fire had damaged the main deck.

In a series of videos published to their Instagram, spokespeople for the GSF said an 'incendiary device' caused a fire onboard the vessel, which the crew was able to extinguish.

Tunisia's National Guard spokesman told Mosaique FM radio that reports of a drone attack on the flotilla 'have no basis in truth'. He added that an initial inspection indicated the explosion originated inside the vessel.

UN Human Rights Council special rapporteur and Tunisian resident Francesca Albanese, who was also featured in videos shared by the GSF, stated that if an attack could be verified, it would be an 'assault and aggression against Tunisia, and Tunisian sovereignty'.

Albanese has been a prominent critic of Israel's military offensive in Gaza and has been subject to sanctions imposed by the US in July, a decision welcomed by Israeli Prime Minister Benjamin Netanyahu.

Flotilla organisers have stated that their mission aims to 'break Israel's illegal siege on Gaza', but they have faced several setbacks. In June, Israeli forces boarded a boat carrying humanitarian aid to Gaza and detained 12 activists, including Thunberg, before deportation.

Last month, a UN-backed body confirmed that there was famine in Gaza, attributing it to Israel's 'systematic obstruction' of aid, which Israel has labeled as misinformation.

Reports of prior drone attacks on aid ships to Gaza add further complexity to this ongoing international dialogue concerning humanitarian efforts in the region.