Israel may soon have to confront more ships trying to break its naval blockade of Gaza.
Both Iran and Hezbollah are said to be sending aid ships, and the Israeli navy plans to stop them.
Some countries are calling for an end to the blockade, but a top Israeli officials warn that could be a disaster.
Even as Israel prepares its inquiry into the flotilla raid last month, it faces new demands from the European Union to end the three year-old naval blockade of the Gaza Strip.
But Yuval Disken, the leader of Israel's Shin Bet Security Agency, has warned a closed session of parliament that abandoning the naval blockade could pose a grave threat to Israel.
Disken says terrorists in Gaza have 5,000 rockets, including some that can hit Tel Aviv, and that opening the sea lanes would allow more weapons to flow into Gaza.
Disken's warning comes as Iran readies two ships with humanitarian aid bound for the port of Gaza, and Medialine reports the terrorist group Hezbollah is also planning to send a ship full of female activists to Gaza.
Meeting with Arab League leader Abu Moussa in Gaza, Hamas Leader Ismail Haniyeh scoffed at Israel's offer to let more goods through by land from Israel. He said allowing tomatoes and mayonnaise is not a relaxation of the siege.
Meanwhile, in a British Broadcasting Network interview, Middle East Quartet Envoy Tony Blair said a balance can be found between Israel's security needs and Palestinian humanitarian needs.
"As fast as the next few days, I hope we can get significant movement on this because otherwise I think the pressure will build up," Blair said.
Hamas, with its charter committed to Israel's destruction, senses world sentiment shifting in its favor. Israel, while it investigates itself, must run a diplomatic marathon to try to keep up its defenses.