The Arab League has called an emergency meeting to be held today in Cairo. Palestinian President Mahmoud Abbas has declared a three-day period of mourning.
As the condemnations escalate, another ship is on its way. The MV Rachel Corrie, its namesake the young peace activist killed by a bulldozer in Gaza, is a converted merchant ship set to reach Gazan waters en route from Ireland.
"This is not the end of our struggle to break the siege," co-founder of the Free Gaza movement and flotilla organizer Greta Berlin told ABC News. "The mission is underway. Our goal is still to reach Gaza to unload the tons and tons of cargo that's on its way."
The MV Rachel Corrie has very few people aboard, Berlin said, as it is a cargo ship and not a passenger boat. The flotilla was Free Gaza's ninth voyage by sea.
The international reaction to the raid has been "horrific, as far as Israel is concerned," said Dr. Robbie Sabel, of Hebrew University of Jerusalem's law faculty. "Civilians were killed and nobody likes to see civilians killed," he told ABC News.
The European Union, the U.N., and a growing number of international observers say that Israel's policy of isolating the region is unsustainable, calling for Israel's blockade on Gaza to be immediately lifted.
Sabel said that under international law, Israel's actions are legal in terms of the blockade. "Israel is in a state of armed conflict with a Hamas regime in Gaza, which Hamas does not deny," he said. "Under the laws of armed conflict, a naval blockade is permissible subject to restrictions — which Israel complied with."
Israel warned the ships to re-route, keeping with the blockade law that maritime traffic must be warned.
"If it was a combatant vessel, it could be attacked. They couldn't be attacked because they are civilians, but they could be arrested," Sabel said. "With the exception of one vessel, the captains complied and sailed into the Israeli port peacefully."
Fallout from the mission is seen throughout today's Israeli newspapers, filled with criticism over the mission.
Shalom Yerushalmi in the Israeli daily newspaper Ma'ariv described the fallout within Defense Minister Ehud Barak's own party, saying that a contingent of Labor Party members, including former defense minister Amir Peretz, may demand a resignation from Barak, who they say "acted irresponsibly and with injudicious force."
Columnist Sever Plotsker of Yediot Aharonot is calling for Barak's resignation now. "There isn't a broom broad enough to sweep this failure under the rug," Plotsker wrote.
About 10,000 Turks marched in protest in Istanbul and Ankara. Public protests also ensued in Amman, Athens, Beruit, Cairo, Geneva, Ireland, Karachi, Lahore, throughout Lebanon, London, New York, Paris, Sarajevo, Tehran, Thessoloniki, Tripoli and Washington, D.C.
ABC News' Clark Bentson and the Associated Press contributed to this report