An Arabic newspaper said the al-Qa’eda network that masterminded the 11 September deadly attacks on New York and Washington had claimed responsibility for the attacks.

The organisation was based in Afghanistan until U.S. forces overthrew the then ruling Taleban government of Kabol in November 2000.

"It has emerged that there is a link with an organisation in Afghanistan in terms of belief and understanding", Foreign Affairs Minister Abdollah Gul told reporters without giving more details.

"The emerging evidence demonstrates that the security services have been very successful in their work", Gul said, quoted by the English language Turkish Daily News. "A trail has been found and relationships have emerged", he added.

"Taking into account the target, the way the attacks were perpetrated and the contacts of the assailants, we assess that the attacks parallel terrorist acts across the world claimed by al-Qa’eda. Security forces continue to work on this", Guler said, adding that both bombers were from the mainly Kurdish eastern city of Bingol, a hotbed of activity by Hezbollah, a Turkish extremist group which has carried out numerous killings in the area as part of its drive to establish an Islamic state.

"It has been determined that Turks were used as sub-contractors in this incident, which was organised by foreign groups associated to al-Qa’eda", Interior Minister Abdolkadir Aksu told the "Yeni Safak" daily, which is close to the government.

The driver Mesut Cabuk had travelled six times to Iran for bomb training. He was suspected, along with the other suicide driver, Gokhan Elaltuntas of having links with the al-Qa’eda terrorist network.

The Anatolia news agency said the man was a member of the Islamic Great Eastern Raiders-Front, or IBDA-C -- the same group which Turkish officials said did not have the capacity to carry out bombings on such a scale.

The pictures of Cabuk and Elaltuntas were splashed on the front pages of Turkish newspapers on Tuesday, prompting a state security court to order a media blackout on the investigation.

The press also named two other Turks who reportedly helped the bombers organise the attacks and provided them with the pickup trucks.

"Security forces continue to work to determine those who abetted the assailants, the other sources behind the attack and other people who were involved", Guler said.

"The investigation will continue in cooperation with international organisations, we will exchange information with countries with which we have agreements on combating terrorism... Nothing in this incident will remain unclear", he said.

One of the four had also fought in Chechnya against Russian forces and joined Turkish Hizbullah in the late 1980s.

But police held back from formally declaring the four as suspects until DNA testing of skin remnants was completed. Newspapers said three of the men's badly mutilated bodies were found at the scene of the carnage and the fourth was missing.

Police have also continued questioning a Turk believed to be the brother of one of Mesut Cabuk.

In Washington, President George W. Bush also pointed the finger at al-Qa’eda and said the Istanbul bombings showed the group was indiscriminate in its attacks.

"We are seeing the nature of al-Qa’eda" Bush said. "The bombings in Istanbul, I was told today, may have taken more Muslim lives than any other religion. They just kill. And they're trying to create fear and chaos."

Prime Minister Recep Tayyip Erdogan repeated that he condemns the terror attacks in Istanbul and noted that, "If there is a message that this terror activity wants to give, we will turn a deaf ear to it".

Speaking at his Justice and Development (AK) Party's group meeting in Parliament on Tuesday, Erdogan stressed that the terror attacks against two synagogues in Istanbul shadowed the peace and trust environment in the country.

Noting that those who slaughtered innocent people cannot be humans, Erdogan responded to criticisms stating that, "all of those who lost their lives or were injured during the terrorist attacks are the citizens of Turkey regardless of their religion" and underlined that he sees no difference between the citizens of Turkey according to their religion.

"The people that died during the attack are the people of this country" he stressed, quoted by the TDN that noted that the Prime Minister was criticised for not directly mentioning that some of those that died during the bomb attack were Jewish.

He pledged that the state would do what is possible to cure the damage of the incident and the attack once more revealed the importance of international cooperation against terror.

"Killing innocent people cannot be justified for any reason. Here, I once more condemn these murders. Regardless of its goal, terror is anti-human. No political reason can justify the killing of innocent people", stressed Erdogan.