Egyptian protestors shout anti-Israel slogans in a rally in Cairo, capital of Egypt, May 31, 2010, after Israeli commandos attacked an aid flotilla carrying hundreds of pro-Palestinian activists, killing at least 19 people in the predawn raid. [Xinhua/Nasser Nouri]

Israel's attack on a Gaza-bound international aid flotilla on Monday has triggered widespread criticism from countries and international organizations around the world.

Up to 19 civilians were killed and some 30 injured in the predawn showdown between Israeli navy and pro-Palestinian activists onboard the flotilla, consisting of nine ships from Turkey, Britain, Ireland, Greece, Kuwait and Algeria loaded with supplies such as cement, water purification systems and wheelchairs.

The incident happened after Isreali soldiers tried to stop the flotilla from reaching besieged Gaza. The Israeli army responded that their commandos opened fire at the ships when they felt their lives were "under threat."

"We found weapons aboard the ship for use against the soldiers," said Israeli Vice Foreign Minister Danny Ayalon at a press conference, adding that the flotilla's behavior was "an act to break the blockade on Gaza."

After the deadly incident, Palestinian President Mahmoud Abbas, who is currently on a visit to Jordan, said "what Israel has committed against the activists of the Freedom Flotilla is a massacre," and called for three-day mourning and flags at half-mast.

Palestinian embassy in Turkey meanwhile called Israel's intervention on aid ships "barbarous."

"The attack is an organized state terrorism against civilians coming all around the world to help oppressed people living under besiege for more than four years. This is a barbarous attack against our people living in Gaza, human rights, and NGOs which defend international laws and organized this convoy," said the embassy.

Turkish President Abdullah Gul said "It is impossible to ignore the lives of defenseless civilians who were trying to take humanitarian aid to Gazan people."

"Actually, Gazan blockade is not a matter between Turkey and Israel, but an international matter. It is a serious tragedy. We expect Israel to lift this inhuman blockade immediately," he said.

Turkey on Monday has decided to recall its ambassador to Israel.

Egyptian President Hosni Mubarak also condemned Israel's excessive use of force against the peaceful aid flotilla, and insisted on Egyptians' solidarity with the people in Gaza and that the inter-Palestinian reconciliation was the only way to lift the blockade and end the humanitarian sufferings in the region.

China on Monday condemned Israel's raid. "We were shocked by the Israeli attack which led to severe casualties and condemn it," said Foreign Ministry spokesman Ma Zhaoxu in a statement.

Ma said China urged the Israeli side to seriously implement relevant UN Security Council resolution and improve the humanitarian situation in Gaza.