A Turkish aid ship that was raided by Israeli forces in May has arrived back in Turkey after its release by Israel.
Nine people were killed on board the Mavi Marmara as it tried to transport aid supplies to Gaza in May, intending to breach an Israeli naval blockade.
The ship, along with two other vessels from the same flotilla that were also seized, is now docked at Iskenderun.
An Islamic charity which organised the flotilla said the ships might be used for another bid to break the blockade.
"If the problem is not solved, many flotillas... will sail to Gaza," Huseyin Oruc of the Foundation for Human Rights and Freedoms and Humanitarian Aid (IHH) told the Reuters news agency on Saturday.
"We have purchased these three boats for Palestinian needs. If it is necessary, we can use easily use them."
Before releasing the vessels from Haifa on Thursday, the Israeli government had sought a promise that they would not be sent to Gaza.
Three non-Turkish boats are still being held, along with the Irish cargo ship Rachel Corrie, which sailed towards Gaza some days later.
Mr Oruc described the Israeli raid on 31 May as "piracy".
He accused the Israeli authorities of painting the Mavi Marmara, a converted cruise liner, to hide the "thousands" of bullet holes in the hull.
"When they captured the boats, the Israelis hid all of this proof on the outside of the boat," he said.
Reporters said the ship did appear to have been freshly painted.
Turkish prosecutors will board the vessels on Monday to look for evidence of what happened during the raid on the six-strong flotilla, which was trying to reach Gaza with 10,000 tonnes of humanitarian aid.
Israel has admitted mistakes were made in intelligence-gathering and planning, but insisted its commandos used lethal force on boarding the Mavi Marmara because activists had attacked them.
But the activists say the troops opened fire as soon as they boarded the vessel, which was in international waters at the time.
The clash provoked an international outcry, and Israel this week agreed to co-operate with a UN investigation. It has also eased the blockade.
Israel and Egypt have imposed the blockade on the coastal territory since the Islamist militant group, Hamas, seized control of it in 2007.