The Rachel Corrie activist cargo ship kept its course for a Saturday arrival in Gaza or confrontation as world anger simmered over Israel's deadly raid on an earlier blockade-busting bid.
"We are not afraid," Irish Nobel Peace Prize winner Mairead Maguire told Ireland's RTE state radio by satellite phone from aboard the aid-laden ship on Friday.
"We started out to deliver this cargo to the people of Gaza and to break the siege of Gaza, that is what we want to do," the 66-year-old said as the vessel steamed towards the Hamas-run Palestinian enclave.
The boat was just hours from Gaza but the 15 aboard Irish and Malaysian activists, four Indonesian crew and a Scottish captain did not intend to leave international waters and run the Israeli gauntlet until after daybreak Saturday, organizers said.
"All on board on the ship were in good spirits, but very anxious as to the actions the Israelis might take," the organizers said late Friday after contacting the ship.
The activists have put Israel in a tight spot at a time when it already faces a serious diplomatic crisis over Monday's botched raid in which its commandos killed nine Turkish activists in the Gaza-bound flotilla.
Israeli Foreign Minister Avigdor Lieberman reiterated the Rachel Corrie would not be allowed to sail freely into Gaza.
"I have just told the Irish foreign ministry director general that the ship will not be able to travel to Gaza without first being inspected," he said on television.
Irish Foreign Minister Micheal Martin urged Israel to show restraint, saying "the Rachel Corrie should be allowed to proceed to Gaza and to unload its humanitarian cargo".
To make matters worse for Israel, three Spaniards who were with the Gaza aid fleet said there were plans to send more aid ships to the enclave.
"We spoke in Istanbul with the rest of our European colleagues about the possibility of sending ships to Gaza in the coming months, some of them possibly from Barcelona," aid worker Manuel Tapial said.
The United States said Friday it was trying to help avert another violent clash at sea involving Israel.
"Everybody wants to avoid another confrontation and avoid a repeat of Monday's... tragic events," State Department spokesman Philip Crowley told reporters.
At the White House, National Security Council spokesman Mike Hammer said the Rachel Corrie should dock at the Israeli port of Ashdod.
"It remains a US priority to provide assistance to the people of Gaza," Hammer said.
"In the interest of the safety of all involved, and the safe transmission of assistance to the people of Gaza, we strongly encourage those on board the Rachel Corrie and other vessels to sail to Ashdod to deliver their materials to Gaza."
Resentment ran high in Turkey, which sent more than half the almost 700 activists aboard the ill-fated six-ship convoy.
In a statement certain to infuriate Israel, Turkish Prime Minister Recep Tayyip Erdogan said Friday he did not view Hamas as a terrorist organization.
"Hamas are resistance fighters who are struggling to defend their land," Erdogan said of the Islamist movement committed to Israel's destruction and blacklisted in the West as a terrorist group.
In Istanbul, a crowd of some 10,000 people held prayers for a journalist among the nine Turks, one of them also a US citizen, killed in Monday's raid.
Chants of "murderer Israel" echoed across the courtyard of the historic Beyazit Mosque, where a huge banner called for the Israeli embassy to be shut down.
In Beirut, Hezbollah chief Hassan Nasrallah called for the formation of a "Freedom Flotilla II," and lauded Turkey's tough stance against Israel's deadly raid on the Gaza-bound aid fleet.
Israel has warned it will stop the blockade-busting bid by Rachel Corrie a 1,200-tonne cargo ship named after a US activist killed in 2003 as she tried to prevent an Israeli bulldozer from razing a Palestinian home.
On Friday, it reiterated its offer, already rejected by the organisers, to deliver the goods to Gaza overland if the ship unloads in Ashdod.
The Israeli authorities and the activists had conflicting versions of what happened during Monday's pre-dawn raid.
Israel has said the commandos only opened fire after they came under attack with clubs, knives, guns and other weapons.
Bulent Yildirim, head of the Islamic charity Foundation of Humanitarian Relief, which spearheaded the Gaza aid fleet, said activists used iron bars in self-defense after Israeli soldiers fired indiscriminately when they stormed the Turkish ferry Mavi Marmara.