Israeli gunboats on Tuesday hit the front of a ship, carrying pro-Palestinian activists and medical supplies, when it approached the territorial waters of the Gaza Strip and turned the boat back, Palestinian officials said.

It is the first time the Israeli navy prevents the boat, chartered by the US-based Free Gaza Movement, after it has completed five successful voyages to break Israel's blockade on Gaza between August and December.

"The gunboats caused damage to the boat, which sailed from Cyprus, and forced it back amid fears that it will sink due to the damage," said Amjad al-Shawa, a Palestinian NGO worker.

Doctors and medical supplies were on board, trying to reach Gaza where Israel has been carrying out unprecedented a real offensive since Saturday, killing more than 350 Palestinians and wounding more than 1,500 people.

Al-Shawa said the boat changed its way to Lebanon where the nearest port is located. However, Mustafa al-Barghouti, a Palestinian lawmaker based in West Bank, said Israel prevents the boat from heading directly for Lebanon, wanting it to go to the international waters first.

"The ship is close to sinking. This is an aggression on a humanitarian work." al-Barghouti added.

Israel imposed a blockade on Gaza Strip last year after Islamic Hamas movement seized the territory by force. The ongoing Israeli airstrikes, the most violent in 40 years of conflict, came as the healthcare system in Gaza suffers from shortage in supplies due to the siege.

(Xinhua News Agency December 30, 2008)