Palestinians ride boats in a preparation ceremony to receive the international aid convoy "Freedom Flotilla" in Gaza Seaport, on May 30, 2010. [Xinhua/Yasser Qudih]

19?people have been killed after Israeli commandos stormed a convoy of ships carrying aid to the Gaza Strip, the Israeli army says, BBC reported.

The clash happened after Israeli soldiers tried to stop the flotilla from reaching Gaza. Israel's private Channel 10 television station said Israeli forces opened fire after being attacked by a number of passengers.

The flotilla of six ships was carrying about 10,000 tons of aid and a group of activists who were making an attempt to break the blockade on Gaza.

Israeli commandos dropped from a helicopter onto the deck of a Turkish ship at about 4:30 a.m. and immediately opened fire on unarmed civilians, said a twitter of the human rights group Free Gaza Movement.

The Israel Defense Forces (IDF) spokesman's office said it could not confirm any of the report at the moment.

Sources told Xinhua that seven of the injured were admitted to Israel's Rambam Medical Center in Haifa. The hospital's spokesman David Ratner said that a 20-year-old, man with moderate injuries was delivered by a helicopter from the sea, but denied he was from the aid ship.

Live images showed Israeli soldiers from a helicopter and a number of speedboats boarding one of the ships at night. Activists wearing life vests were treating what appeared to be injured people.

The English channel of Al Jazeera television said the clash happened in international waters off the Gaza coast after activists ignored an Israeli order to turn back.

The flotilla had set sail from a port in Cyprus on Sunday and was expected to reach Gaza by Monday morning, Al-Jazeera reported.

The flotilla, originally made up of nine ships from Turkey, Britain, Ireland, Greece, Kuwait and Algeria, was carrying cement, water purification systems and wheelchairs.