ISTANBUL, Turkey - Turkey's prime minister Thursday strengthened his role as a leader in the Islamic world, basking in Arab leaders' applause as he unleashed invective against Israel and questioned Washington's dominance at a summit in the onetime seat of the Ottoman Empire.

Recep Tayyip Erdogan's international profile has risen sharply since the Israeli commando raid on aid ships bound for Gaza, with Muslims across the Middle East holding him up as a hero for his tough talk against Israel. The thunderous reception by fellow Muslim leaders appeared to confirm his status as the man of the moment.

The Turkish-Arab Economic Forum opened with calls for an international investigation into the May 31 Israeli raid that killed eight Turkish activists and a Turkish American teenager.

"Are we going to remain silent over the murder of nine people? We can't turn a blind eye to this banditry in international waters," Erdogan told the forum.

Arab League chief Amr Moussa accused Israel of continued "atrocity and assault" in violation of human rights and international law, and praised Turkey for challenging Israel on the raid. Israel insists its commandos acted in self-defense after being attacked by pro-Palestinian activists on the aid ships.

'Grave concern'

At the forum, Turkey and 20 Arab nations issued a joint statement expressing "grave concern and condemnation for the Israeli aggression" on the Gaza-bound aid ships. Erdogan said Israel's partial easing of its Gaza blockade was not enough.

Turkey's popularity in the Muslim world has surged not only for the stand it has taken against the Israeli blockade but also for objecting to new sanctions against Iran - which the U.N. Security Council passed Wednesday after rejecting an Iranian nuclear-fuel swap deal brokered by Ankara.

Turkey, a non-Arab, predominantly Muslim country, has for months been drifting away from the West and staking out a claim as a global player.

In an apparent jab at U.S. foreign policy, Erdogan said: "Arms, embargoes, and exclusion are not working" - adding that the world was paying a heavy price for such strategies in Iran and Afghanistan.

But he also rejected suspicions that he was shifting toward the East and reiterated his nation's commitment to joining the European Union - although he accused the Europeans of acting in bad faith with a "secret agenda" against Turkey.

'Free movement'

"There are those within the European Union who are trying to slow down the negotiating process, those who want to prevent the process," Erdogan said.

France and Germany are the most prominent European countries seeking to block Turkey's entry into the 27-nation bloc. Opponents say Turkey has not moved fast enough on promised reforms, and Turkey's 1974 occupation of northern Cyprus is a stumbling block. The Greek-speaking half of the island entered the EU in 2004.

During the forum, Turkey and the Arab countries of Syria, Jordan, and Lebanon also agreed to set up a council to create "a zone of free movement of goods and persons" among them, and urged others to join what Turkish Foreign Minister Ahmet Davutoglu said should not be seen as an alternative to the European Union.

He said that Turkey was still eager to join the EU but that the bloc "cannot and should not restrict [Turkey's] relations with its neighbors."

Yet in a clear reference to the Ottoman Empire, Davutoglu said that "long before the dream of creating the EU existed, we had close trade relations among us in this region."