Israeli warships attacked at least one of the six ships carrying pro-Palestinian activists and aid for blockaded Gaza today, killing at least ten and wounding an unknown number of people on board, reports said.
There are eight Irish nationals on board the flotilla of six ships, including three Irish activists on one of the boats, the Challenger II. They are Dr Fintan Lane, Fiachra O Luain and Shane Dillon. Attempts to contact their ship have been unsuccessful.
The Israeli military said the violence turned deadly after one of the activists grabbed a weapon from one of the commandos. The weapon discharged, though it was not clear whether the activist fired it or if it went off accidentally.
Israeli Arab groups said a prominent activist is among the wounded.
The Israeli military denied that its forces attacked the boats, but said they would enforce the decision to keep them away from Gaza.
They said the troops faced resistance and that soldiers were under orders to use fire only if their lives were in danger.
Omer Faruk Korkmaz, an official of the pro-Islamic aid group IHH, that led the aid shipment, said in Turkey: "We were not expecting such an operation in international waters.
"Israel has been caught red-handed and the international community will not forgive it."
Mr Korkmaz said the ship was being escorted to Haifa.
A Turkish website showed video of pandemonium on board one of the ships, with activists in orange lifejackets running around as some tried to help an activist apparently unconscious on the deck.
The site also showed video of an Israeli helicopter flying overhead and Israeli warships nearby.
The head of Gaza's Hamas government, Ismail Haniyeh, condemned the "brutal" Israeli attack.
"We call on the secretary general of the UN, Ban Ki-moon, to shoulder his responsibilities to protect the safety of the solidarity groups who were on board these ships and to secure their way to Gaza," he said.
Turkey summoned the Israeli ambassador to the foreign ministry today to discuss the incident.
The al-Jazeera satellite channel reported by telephone from the Turkish ship leading the flotilla that Israeli Navy forces fired at the ship and boarded it, wounding the captain.
The Turkish NTV network also reported an Israeli takeover with gunfire, saying at least two people were killed.
The al-Jazeera broadcast ended with a voice shouting in Hebrew: "Everybody shut up!"
Reports of an Israeli attack came just after daybreak, with the flotilla still well away from the Gaza shore. Israel had declared it would not allow the ships to reach Gaza.
Turkish television stations said today police had blocked dozens of stone-throwing protesters shouting "Damn Israel", who tried to storm the Israeli Consulate in Istanbul following news of the attack.
Yesterday Huwaida Arraf, one of the flotilla organisers, said the six-ship group began the journey from international waters off the coast of Cyprus on in the afternoon after two days of delays.
She said they had expected to reach Gaza, about 250 miles away, this afternoon, and that two more ships would follow in "a second wave".
The flotilla was "fully prepared for the different scenarios" that might arise, and organisers were hopeful that Israeli authorities would "do what's right" and not stop the convoy, she said.
"We fully intend to go to Gaza regardless of any intimidation or threats of violence against us," she said. "They are going to have to forcefully stop us."
As night fell yesterday, three Israeli navy missile boats left their base in Haifa, steaming out to sea to confront the activists' ships.
Two hours later, Israel Radio broadcast a recording of one of the missile boats warning the flotilla not to approach Gaza.
"If you ignore this order and enter the blockaded area, the Israeli Navy will be forced to take all the necessary measures in order to enforce this blockade," the radio message continued.
Al-Jazeera reported that the ships had changed course to try to avoid a night-time confrontation, preferring a daylight showdown for better publicity.
The flotilla, which includes three cargo ships and three passenger ships, is trying to draw attention to Israel's three-year blockade of the Gaza Strip. The boats are carrying items that Israel bars from reaching Gaza, like cement and other building materials.
The activists said they also were carrying hundreds of electric-powered wheelchairs, pre-fabricated homes and water purifiers.
Israeli foreign ministry spokesman Yigal Palmor said yesterday that after a security check, permitted humanitarian aid confiscated from the boats would be transferred to Gaza through authorised channels.
Israel has condemned the flotilla as a provocation and vowed to block it from reaching Gaza.
Israeli military officials said they hoped to resolve the situation peacefully but were prepared for all scenarios. Naval commandos have been training for days in anticipation of the stand-off.
Mr Palmor said foreigners on the ships would be "sent back to their countries" and activists who did not willingly agree to be deported would be detained.
A special detention centre has been set up in the southern Israeli city of Ashdod.
This is the ninth time that the Free Gaza movement has tried to ship in humanitarian aid since August 2008.
Israel has let ships through five times, but has blocked them from entering Gaza waters since a three-week military offensive against Gaza's Hamas rulers in January 2009. The flotilla bound for Gaza is the largest to date.
About 700 pro-Palestinian activists are on the boats, including 1976 Nobel Peace Prize laureate Mairead Corrigan Maguire from Northern Ireland, European politicians and a Holocaust survivor.