Israeli police confirmed that Halper had been taken into custody as he crossed the heavy militarized Eretz crossing from Gaza into Israel.

He was taken to a police station in the southern town of Sderot were he was questioned and later released. A police spokesman said a decision would shortly be made as to whether to charge Halper, an anthropologist at Israel's Ben Gurion University.

In addition to breaking Israel's naval blockade of Gaza, Minnesota-born Halper is also accused of going into Palestinian territory, which is off limits to Israeli citizens according to Israeli law.

Initially Israeli security officials refused to let Halper pass through the Erez crossing, telling him that he could leave Gaza the same way he had entered, i.e. via boat back to Cyprus and then back to Israel even though Halper lives in Jerusalem which is about an hour's drive from the Erez border.

Halper said that eventually they relented and let him enter the border crossing where he was subsequently arrested. He added that although he had expected to be questioned he hadn't expected to be harassed.

Halper, who has dual American-Israeli nationality, is no stranger to controversy and standing up for Palestinian rights, and in his capacity as the leader of ICAHD has been arrested and detained on numerous occasions as he attempted to stop Israeli security forces from destroying Palestinian homes allegedly built without permits.

Human rights organizations argue that Israel implements a discriminatory policy toward Palestinians trying to enlarge current or build new homes and that obtaining the requisite permits is extremely difficult.

In the interim, the international human rights activists from the two boats, which reached Gaza port from Cyprus late Saturday afternoon provoking tumultuous applause and excitement from hundreds of Palestinians who had lined the shore waiting to greet the visitors, have been pushing the envelope further.

In a bid to further challenge Israel's crippling blockade of Gaza which has decimated an already fragile economy and ensured poverty and deprivation for Gaza's 1.5 million inhabitants, they accompanied Gazan fishermen out to sea on Sunday in defiance of Israel's naval blockade.

Israel has enforced a fishing limit of six miles, forcing thousands of Gaza's fishermen out of business, and thereby exacerbating the high unemployment in the territory which stands at close to 60 percent, and severely limiting the ability of the remaining fishermen to pursue a viable living.

Under the Oslo Accords of 1993 Gazan fishermen were allowed to go 20 nautical miles out to sea, however Israel restricted this to the current six nautical miles, following Hamas' takeover of the strip last year.

But in order to pursue the larger shoals of fish and catch sufficient supplies to sustain their livelihoods it is necessary to go further out.

Greta Berlin, an American spokeswoman for the activists, related their trip.

"Twenty of us arrived at the port about 4:30 am, amid the dozens of security men standing there guarding us. We were told we'd have to wait, because the fishermen were afraid to go out to sea with us, uncertain whether they would be shot at or worse," recalled Berlin.

"Finally, four hours later, six boats showed up, and we boarded, two or three to a boat. All the Palestinians said they wanted to go past the six mile limit. They were as eager as we were to test the noose hanging around their necks.

"At eight miles, three Israeli patrol boats showed up, buzzing up and down in front of us, a man on a machine gun at the back of each one. The boat I was accompanying was owned by six cousins, the youngest 15, and they were, at first, nervous when the patrol boats showed up," said Berlin.

The Israelis, however, took no action.

"Six hours later, the men had caught more fish in their nets than they had in four years. They were ecstatic, and I got to watch them haul the tons of fish up and over the back of the boat. They were overjoyed with their catch, and said the boats that went out would provide an income for over 16 families for a month," Berlin said.

The next question now facing the siege-breakers is whether the Israeli authorities will allow them to return to Cyprus on Thursday unhindered or whether their boats will be stopped and those on board arrested and interrogated.

While the derring-do of the human rights activists has been lauded by Irish Nobel Peace Prize laureate Eileen McGuire, who herself was shot at by Israeli soldiers during a protest against the separation wall in the West Bank, and supported by Richard Falk, the U.N.'s special rapporteur on the situation of human rights in the Palestinian territories, the Israeli authorities have warned that they will not tolerate any further transgressions.

The Israelis have so far wanted to avoid any negative publicity, which would have arisen following a physical confrontation with the boats at sea, but it remains to be seen exactly what action will be taken on the return voyage to Cyprus.