(AP Photo/Hatem Moussa)
The flotilla was initially to set sail toward Gaza on Saturday afternoon and approach the territory today, about 24 hours behind schedule, said Greta Berlin, one of the activists.
A showdown with the Israeli navy appeared inevitable. Israel's deputy foreign minister, Danny Ayalon, reiterated Saturday that the ships would be intercepted. He also denounced the sea convoy as a provocation and violation of maritime laws.
Israel and Egypt imposed a blockade on Gaza after the Islamic militant Hamas seized the territory by force three years ago.
In Gaza, Prime Minister Ismail Haniyeh of Hamas said the flotilla signals the end of the blockade.
"If the ships reach Gaza, it's a victory for Gaza," Haniyeh told some 400 supporters Saturday, after touring Gaza City's small fishing harbor where several smaller vessels breaking the blockade have docked in the past. "If they are intercepted and terrorized by the Zionists, it will be a victory for Gaza, too, and they will move again in new ships to break the siege of Gaza."
In Cyprus, organizers of the flotilla said the ships would make their 15-hour journey to Gaza at midnight Saturday.
The organizers said the two dozen would-be passengers, including 19 European legislators and an elderly Holocaust survivor, were expected to join the ships anchored in international waters off the island late Saturday.
The Cypriot government at first would not allow smaller boats to ferry the group to the flotilla, Berlin said. Authorities in Cyprus said the decision was made to protect the island's "vital interests" -- including economic ties with Israel.
Organizers then appealed to the Turkish government to get the group out via a Turkish-controlled northern Cyprus port. Turkish Cypriot officials have said they want to help the group as much as they can.
But a diplomatic tangle wasn't the only factor delaying the mission. Mechanical problems forced the flotilla to shrink from eight ships to five, and the boats have lost the ability to communicate by satellite phone twice, Berlin said.
Israeli authorities have said they will not comment on military tactics, but are determined to intercept and search the vessels, then tow them to an Israeli port. Israel has prepared a makeshift detention center in its southern port of Ashdod, and officials have said the activists sailing on the ships face deportation or arrest. The cargo, meanwhile, would undergo a security check, and then be transferred to U.N. agencies for distribution in Gaza.
"We will not let this flotilla get through. It harms Israeli security," Israel TV's Channel 10 on Saturday quoted Ayalon as saying.
Still, the aid convoy poses a serious dilemma that was debated at the highest levels of the Israeli government this week.
Scenes of Israeli naval commandos taking over vessels with aid shipments and detaining high-profile activists could further harm the Jewish state's image. However, Israel is concerned about setting a precedent and eroding the blockade if it lets the vessels dock in Gaza.
Critics say the blockade has been counterproductive, failing to dislodge Hamas while deepening poverty in Gaza. There have been growing demands by the international community that Israel ease its grip or lift the closure altogether.
Earlier this week, Turkey urged Israel to end the blockade and said it was using diplomatic channels with Israel to avert a showdown over the flotilla. However, Ankara has also said the sea convoy, arranged in part by a Turkish aid group, is a private initiative.
Turkish-Israeli relations cooled after Israel's military offensive against Gaza in the winter of 2008-2009.
In Gaza City, Haniyeh, the prime minister of Gaza, praised Turkey as a leader among Muslim nations. Gaza's harbor was decorated with Turkish flags.
"This fleet indicates that Turkey ... is leading strategic changes in the region based on disconnecting itself from the Zionist enterprise and joining the Muslim nations," he said.
Israel, which considers Hamas a terrorist group, says the blockade is needed to prevent the Islamic militants from developing weapons. It has condemned the flotilla as a publicity stunt, insisting there is no humanitarian crisis in Gaza and offering to deliver the aid through official channels.
Since Hamas took power in 2007, Gaza has come to rely on a series of underground tunnels connecting it with Egypt to smuggle in goods ranging from weapons to motorbikes. Six Gazans were killed and 14 injured Saturday afternoon when a gas canister exploded in one of those tunnels, wounding and partially suffocating workers who were performing maintenance operations, according to Gazan security officials who spoke on condition of anonymity.
Associated Press writers Rizek Abdel Jawad in Gaza City and Menelaos Hadjicostis in Nicosia, Cyprus, contributed to this report.