Occupied Jerusalem: Israel deported activists from an aid ship it intercepted in the Mediterranean en route from Lebanon to the Gaza Strip, but allowed blood donations that were on board to enter Gaza on Friday, the Israeli military said.

Meanwhile, Gaza militants launched two rockets into Israel, the Israeli military said, causing no injuries but punctuating the fragility of a Gaza cease-fire nearly three weeks after the end of Israel's offensive against Hamas.

The aid ship was docked on Friday at the Ashdod port, where it was towed Thursday after being stopped and boarded by Israeli troops. Israel and Lebanon are officially at war, and Israel said it was concerned about the ship's cargo and called the boat a "provocation."

Israel, which is enforcing a naval blockade aimed at Gaza's Hamas rulers, has allowed several similar aid ships into Gaza and has turned several more back, but had never before boarded or detained one.

Fifteen of the people on board, Lebanese and Syrian nationals, were deported overnight to Lebanon and Syria through the borders with those two countries, the military said. Three others - two Indians and a Briton - remained in police custody pending deportation from Israel's international airport, police spokesman Micky Rosenfeld said. It was not immediately clear when the boat would be allowed to sail.

Some 1,000 units of donated blood were quickly unloaded and sent into Gaza, according to military spokesman Peter Lerner. The rest of the supplies on board were being examined and would also be sent to Gaza, he said.

Despite Israeli concerns, no weapons were found on board. The organisers of the aid ship, Lebanese political and human rights activists, said the cargo comprised medicine, food, toys and basic humanitarian supplies such as mattresses and blankets.

Israel unilaterally halted its devastating Gaza operation on January 18, and Hamas followed with an announcement that it would hold its fire.

Egypt's attempts to mediate a long-term cease-fire have not succeeded so far. Hamas is demanding that Israel open Gaza's blockaded border crossings as part of any agreement, but Israel says it will not turn the crossings over to Hamas control.

The attempts to negotiate a cease-fire are unfolding in the shadow of Israel's national election on Tuesday, as Israel's leaders compete over who can take the toughest stand against Hamas. Polls show the likely winner is hard-line Likud Party leader Benjamin Netanyahu, who says the current government ended the Gaza operation too early, without causing enough damage to the Hamas.

Militants have sporadically fired rockets into Israel since the operation ended, and killed one soldier in a border bombing attack. Israeli troops have killed three Palestinians who Gaza officials identified as farmers in border shootings and have repeatedly bombed smuggling tunnels under the Gaza-Egypt frontier.

FRiday's rockets were launched from northern Gaza, the military said. They followed an incident late Thursday on the Gaza-Israel border in which Israeli forces shot and killed a Palestinian who the military said approached the fence armed with a grenade.

The UN agency in charge of Palestinian refugees says it has not been able to send in trucks carrying plastic bags, threatening its food distribution programme.

The UN Relief and Works Agency (UNRWA) has also been prevented from sending in trucks carrying notebooks and paper to print textbooks for the 200,000 Gaza students taught in the agency's schools, UNRWA spokesman Christopher Gunness said.