Five Irish citizens including author Naoise Dolan and Independent TD Barry Heneghan have been detained by Israel when their flotilla of humanitarian aid to the Gaza Strip was intercepted, organisers have said.

They had been part of the Thousand Madleens flotilla, a group of nine boats that had been about 120 nautical miles from Gaza before it was intercepted.

It had been set to arrive at the embattled enclave on Thursday.

It was travelling behind the previous Global Sumud Flotilla that was intercepted last week.

“Our plan A was always to deliver the aid, but we knew this could happen, and we accepted it as a calculated risk,” Ms Dolan, the author of Exciting Times and The Happy Couple, said in a voice note sent before her interception.

“We don’t take stupid risks, we don’t take unnecessary risks, but we do take risks that we see as required in order to challenge Israel’s illegal blockade and defend Palestinian self-determination.”

The other Irish citizens on board the intercepted boats were named by organisers as Fionn Macarthur, Veronica O’Keane and Mutaz Jadaan, a dual Irish-Jordanian citizen.

The Freedom Flotilla Coalition (FFC) is an international network of pro-Palestinian activist groups that organises civilian maritime missions aimed at breaking Israel’s blockade of Gaza to deliver humanitarian aid to Palestinians in the enclave.

A spokesman for Ms Dolan said she was on board a vessel named the Milad when it was intercepted by Israeli forces in the eastern Mediterranean at about 4.30am.

“Her family and friends are monitoring the situation closely and her legal team has already mobilised. There are no communications with the boat or flotilla members at the moment,” the spokesman said.

The flotilla’s vessels and passengers were safe, had been transferred to an Israeli port and were expected to be deported promptly, Israel’s foreign ministry said in a statement on X.

“Another futile attempt to breach the legal naval blockade and enter a combat zone ended in nothing,” the ministry said.

The incident was the second such event in recent days, after Israel had intercepted about 40 vessels and detained more than 450 activists in an aid convoy, the Global Sumud Flotilla, that was also attempting to deliver supplies to Gaza.

‘I’m prepared for what might happen’: novelist Naoise Dolan approaches Gaza on next flotillaOpens in new window ]

The FFC said Israeli forces “hijacked the humanitarian fleet”, adding that the “ships were illegally intercepted … Participants – humanitarians, doctors and journalists from across the world – have been taken against their will and are being held in unknown conditions.

“The Israeli military has no legal jurisdiction over international waters,” it said. “Our flotilla poses no harm.”

The ships carried aid worth more than $110,000 (€94,500) in medicines, respiratory equipment and nutritional supplies intended for Gaza’s starving hospitals, it added on its Instagram account.

Gaza authorities say about 67,000 people have been killed and the Palestinian enclave devastated by Israel’s assault since the October 7th, 2023 attack by Hamas.

More than 10% of Gaza’s population killed or injured: the cost of two years of warOpens in new window ]

Israel says 1,200 people were killed and 251 taken to Gaza as hostages in the Hamas attack. – Additional reporting: Reuters