A group of 14 Irish citizens have been detained by Israel following the boarding of two Irish and Canadian ships sailing to Gaza.

The Department of Foreign Affairs said those on board the two boats have arrived in the Port of Ashdod where they are being detained, pending deportation.

A consular official from the Irish embassy in Tel Aviv is travelling to Ashdod to visit them.

Tánaiste and Minister for Foreign Affairs Eamon Gilmore said that his initial reaction to the incident had been relief that there had been no violence and that all Irish nationals were safe.

He said his department had been in contact with the Israeli authorities and had urged that all possible restraint be exercised by Israel in carrying out any interception.

Mr Gilmore said the Government did not agree with the Gaza blockade and that it was contrary to international humanitarian law in its impact on the civilian population of Gaza.

He said Department of Foreign Affairs' advice to anyone seeking to sail to Gaza in an effort to challenge the blockade remained unchanged. He said he could not recommend this because of the risk to health and safety.

"I do not accept Israel's right to apprehend in international waters anyone seeking to sail to Gaza purely in order to peacefully protest the blockade or for the purpose of transmitting humanitarian aid," said Mr Gilmore.

This evening, the Irish ship to Gaza campaign said it had received a text message from former Ireland rugby player Trevor Hogan, who is one of the people being detained.

In his text, the campaign claim, Mr Hogan said that the two boats were nearly destroyed and that the campaigners were being held against their will.

He also called on the Government to intervene for their release, according to the campaign.

Earlier, the Israeli military said that the two ships, which had been sailing to Gaza, had been boarded by the Israeli navy.

A military source said nobody was injured in the operation.

A Deparment of Foreign Affairs spokesperson corroborated the Israeli version that there were no injuries during the operation.

Contact was lost with the ships at this morning. Israel's military chief ordered the navy to intercept two boats.

Lieutenant General Benny Gantz issued the instructions after "all attempts to contact" activists aboard the Canadian and Irish vessels had failed, the Israel's military said.

Earlier, the Israeli military confirmed it had made radio contact with both vessels, telling them they were about to enter an area "under a maritime security blockade", appearing to contradict the later statement.

"The Israel navy advised the vessels that they may turn back at any point, thereby not breaking the maritime security blockade, or sailing to a port in Egypt or the port of Ashdod."

"The activists refused to cooperate," it added.

The Irish boat is carrying 15 passengers and crew members, while the Canadian boat has 12 people on board, five of them journalists, and is carrying medical aid and letters of solidarity, organisers said.

Yesterday, Israeli vessels came within six nautical miles of the two vessels, and Israeli spotter planes were observed overhead, said Fintan Lane, a coordinator of the Irish Ship to Gaza campaign.

But fears of an overnight boarding did not materialise.

Israel says its blockade is necessary to prevent weapons from entering the coastal territory, which is run by Hamas.

Activists organised a major attempt to break the Israeli blockade in May 2010, when six ships led by the Turkish Mavi Marmara tried to reach Gaza.

Israeli troops stormed the Marmara, killing nine Turkish activists and sparked a diplomatic crisis with Ankara, which expelled the Israeli ambassador and has cut military ties with Israel.

Two months ago, a UN report on the flotilla raid accused Israel of acting with "excessive force" but found that its naval blockade on the coastal territory was legal.