The event was being attended by Turkish President Suleyman Demirel and Prime Minister Mesut Yilmaz, and also Prince Andrew, the Duke of York and Israeli President Ezer Weizman.

According to the semi-official Anatolia news agency, four members of a suicide squad planned to crash a plane loaded with explosives while the ceremony was taking place.

The agency said the kamikaze squad were arrested during a trial run using a private plane.

President Demirel (left) welcomed many world leaders for the celebrations

The ceremony was held on Thursday without a hitch at the mausoleum of Mustafa Kemal Ataturk, who set up Turkey's secular republic on 29 October 1923, following the collapse of the Ottoman Empire.

A total of 24 members of the group have been arrested, and guns, dynamite, and gas bottles recovered, the agency said. They are alleged to be linked to a radical Islamic group, known as the Anatolian Federated Islamic State (Afid).

Afid is an illegal organisation based in Germany, aiming to set up a state based on Sharia principles.

Last year Turkey's first Muslim-led government was forced out of power, with support from the pro-secular army.

Hijack marred celebrations

The anniversary celebrations were marred by an unconnected event - the hijack of a Turkish airliner which was seized on an internal flight on the same day.

Nearly 40 passengers and crew on board were released unharmed after the plane had spent several hours on the ground at Ankara airport.