The organisation behind the Gaza aid flotilla says it has lost contact with another ship trying to bring supplies to the Palestinian territory.
The Free Gaza movement says it suspects the Israelis of having sabotaged the communication links.
The Rachel Corrie, chartered by an Irish group with fifteen people on board, is expected off the coast of Gaza tomorrow.
The crew have denied negotiating with Israel about the possibility of docking in the Israeli port of Ashdod.
The Turkish prime minister has denied claims that some activists are still missing after the Israeli assault on the flotilla.
Recep Tayyip Erdogan has visited in hospital those injured during the raid. Medical teams have been sent to Israel to repatriate the remaining five Turkish nationals.
Amid emotional scenes, Turkey has held funerals for the nine activists who were killed after their bodies were flown back to Istanbul.
The Turkish president said relations with Israel would never be the same, and there was now an irreparable and deep scar.