A boat carrying 21 pro-Palestinian activists from 11 countries is heading for Gaza port in defiance of Israeli navy interception and intimidation, the voyage's organizer, the Free Gaza Movement, said on Tuesday.

The vessel, with three tons of medical aid, toys, and rehabilitation and reconstruction kits on board, left the Cypriot port of Larnaca on Monday morning. It first sailed southward in the direction of Egypt, but then turned southeast heading for Gaza port.

According to the latest information from the movement, the boat, Spirit of Humanity, was only 21 miles away from Gaza port.

Activists on board accused the Israeli navy of periodically "illegally jamming the boat's radio," making navigation difficult.

"The Israeli navy has sent two to eight ships," the organizers said in an update of the situation via Twitter, the social networking site.

According to the latest message, the boat was "still be escorted by two Israeli gunboats."

Earlier, Israeli gunboats in international waters ordered the boat to return to Larnaca, Cyprus, saying it would not be allowed to proceed to Gaza.

The U.S.-based Free Gaza Movement last year successfully challenged the Israeli embargo on Hamas-controlled Gaza and sailed the first international ships to Gaza port since 1967. But the movement's attempts earlier this year failed, either due to technical problems or Israeli blockades.

This time, among the passengers onboard the boat are Nobel laureate Mairead Maguire and former U.S. Congresswoman Cynthia McKinney.

Huwaida Arraf, spokeswoman for the movement, said it does not seek a confrontation with the Israeli forces.

"We have traveled from Cypriot waters to international waters and will enter Gazan waters. We've never gone anywhere near Israel," she said.

"Israel's closure of Gaza is an act of collective punishment and a blatant violation of the international law," Arraf said.

More than 2,400 homes were destroyed in Gaza during the Israeli military operation in December last year and January, as well as 30 mosques, 29 educational institutions, 29 medical centers, 10 charitable organizations, and five factories, a press release by the movement said.

International donors have pledged more than US$4 billion in aid for Gaza in the aftermath of the Israeli military action, but little aid or reconstruction supplies have been allowed into the enclave.

(Xinhua News Agency July 1, 2009)