Tensions are building as eight ships carrying thousands of tons of material and supplies are headed for Gaza to break a blockade-Israel imposed the border closure after Hamas seized power over Gaza in 2007.

The boats left ports in Britain, Greece, Ireland and Turkey yesterday. The so-called Freedom Flotilla will assemble at Cyprus Friday and make the final one-day journey to Gaza collectively.

Israel has said it will not allow the aid convoy to reach Gaza. It has imposed a blockade on Gaza after the Islamist militant group Hamas seized control of the territory in 2007. The Israeli military has sought to prevent militants from receiving materials that can be used to attack Israel, and has stopped other vessels carrying aid to Palestinians in the past.

The Israeli Army calls the flotilla a provocation, orchestrated by Hamas under the guise of delivering humanitarian relief to residents of Gaza. It says the humanitarian situation there is "good and stable."

A spokesman for the Israeli Defense Forces told VOA that any organization wanting to deliver supplies to Gaza is free to do so, but in coordination with the Israeli government. "Anything that could happen we're ready for. That's all I can tell you," he said.

Israel says it has set up a detention center for the activists who attempt break the blockade.

Christopher Gunnes is a spokesman with the United Nations Relief and Works Agency for Palestinian Refugees. He said that the situation on the ground in Gaza is dire.

"The idea that Gaza has everything that it needs is absurd. Basic things are getting in, yes," he said. "They're getting in through the tunnels."

"And that means that the number of those who can't afford to feed their families - special hardship cases, we call them, has gone up in the last year alone from 100,000 to 300,000 because prices of goods coming through the tunnels are going up and up and up. There is undoubtedly a serious humanitarian crisis going on in Gaza and to say anything else is simply absurd," he added.

Several hundred journalists and activists are reported to be on board the ships, including an aged Holocaust survivor and a Nobel Peace Prize laureate.