The Israel Navy on Monday turned away a Libyan ship heading to Gaza with 3,000 tons of humanitarian aid, ending the most high-profile effort yet to break a blockade of the Hamas-ruled territory.

The Al Marwa was approaching the Gaza coast when it was stopped by an Israel Navy vessel. The navy vessel ordered the Libyan ship via radio contact to turn back, said Israeli Foreign Ministry spokesman Yigal Palmor, adding that no force was used.

In Gaza's small port, spectators, journalists and dozens of porters had assembled to await the arrival of the Libyan ship.

It was not immediately clear where the Libyan ship was now headed. If unable to unload the cargo in Gaza, the ship would return to Libya, said a senior Libyan government official, who spoke on condition of anonymity because he was not authorized to discuss the ship's journey with the press.

"The Israeli warships are making it difficult for the ship to reach the Gaza coast, in spite of the fact that this is a civilian ship, sent to help Palestinians during the siege," the official said.

Gaza's borders have been largely sealed by Israel and Egypt since the Islamic militant Hamas group seized control by force in June 2007.

At times, restrictions were eased to allow the movement of medical patients, Muslim pilgrims, humanitarian supplies and a trickle of commercial goods.

However, Israel re-imposed a tight closure November 5 to force Hamas to halt rocket fire on Israeli border communities. The closure has led to shortages of many basic goods.

Since the summer, international activists have organized three trips from Cyprus to Gaza on smaller vessels. Israel did not intercept the activists' boats, which carried some medicine and other supplies.

The trip by the Libyan ship, loaded with food, powdered milk and blankets, marked the most notable attempt yet to break the blockade.

The international community, including Arab countries, has not recognized the Hamas government. Nonetheless, there has been growing concern over the deteriorating humanitarian situation in Gaza.

Last week, Arab foreign ministers said in a joint statement in Cairo that their governments would send food and medicine to Gaza. They did not say specifically whether they would deliver the aid by sea or by land.

The foreign ministers said they would coordinate with Egypt to ensure the supplies enter Gaza, suggesting they would take the land route, rather than confronting Israelis at sea.

However, Egypt has also kept the Rafah crossing with Gaza closed most of the time.

Hamas spokesman Fawzi Barhoum on Monday urged Egypt to open Rafah and allow international aid to reach Gaza. "We believe that there is no justification to keep the Rafah terminal closed," Barhoum said, adding that it causes the slow death of 1.4 million Palestinians in Gaza.