Four suicide bombers who killed more than 50 people in Istanbul over the past week were Turkish citizens, Prime Minister Tayyip Erdogan said today.
Speaking at the funeral of two police officers killed in attacks on Thursday, Mr Erdogan said it was a matter of shame for Turkey that its own citizens were responsible. He also reaffirmed Turkey's belief that the bombers had links with foreign groups.
Turks are staging silent "peace protests" today to express their grief and anger over truck bomb attacks which killed more than 50 people in the worst week of peacetime violence in Turkey's modern history.
Turkish trade unionists and non-governmental groups appealed to people to turn out in major cities to register their revulsion at the blasts, whose victims have included Muslims, Jews and Christians.
A statement purporting to come from a unit of Osama bin Laden's al-Qaeda network said it carried out the twin strikes on the British consulate and the London-based HSBC bank which killed at least 27 people and wounded more than 400. Police have reportedly detained 18 people in connection with their investigation.
Five days earlier 25 people were killed in similar suicide attacks on two synagogues. Israeli intelligence said it had sent agents to help investigate the attacks and British anti-terrorist police have also arrived In Istanbul.
A small Turkish radical Islamist group has also claimed responsibility for the carnage. A statement apparently from the Abu Hafz al-Masri Brigades said it had carried out the latest attacks. It could not be independently authenticated. The Abu Hafz claim, in Arabic, said Turkey was targeted because of its membership in the "crusader" NATO alliance and its ties with the "Zionist entity" Israel.
A Turkish group called the Islamic Great Eastern Raiders Front (IBDA-C) has also claimed joint responsibility with al-Qaeda for all four Istanbul attacks.
Turkey's National Security Council, an advisory body grouping political leaders and influential military commanders, issued a statement last night saying Turkey was determined to beat international terrorism.
US President George W Bush said Turkey, a NATO ally long held up by the United States as a model for Islamic democracy, had become a new front in the "war on terror." The US joined Britain in warning its citizens to defer non-essential travel to Turkey.
But NATO Secretary-General George Robertson vowed the military alliance would go ahead with its summit in Istanbul next June.