Service for consulate dead
Among the church-goers were the UK ambassador to Turkey
Angry and bewildered, Turkey is mourning its dead
Bombings have all the hallmarks of al Qaeda, UK says
Bombings are wake-up call to Islamic nations
Bush: Terrorists' 'hope to intimidate and demoralize'
Blair: 'No holding back' in 'confronting this menace'
ISTANBUL, Turkey -- A memorial service has been held Sunday for the victims of a twin attack on British interests in Istanbul.
Dozens of mourners attended the service at the small Crimean Christ Church in central Istanbul including the wife and children of the UK Consul-General Roger Short who died in the bomb blast at the British consulate Thursday.
Two other Britons died, as well as an Australian, and two Armenians.
Thirty people, mainly Turks, died in the two attacks on the consulate and the offices of the London-based bank HSBC. Funerals have been held during the past few days.
Turkish Prime Minister Recep Tayyip Erdogan talked of the country's shame that four of the bombers were Turks, probably aided by international organizations.
He called for more international cooperation in the fight against terrorism.
Instructions have been sent to religious institutions for sermons on tolerance to be delivered marking the end of Ramadan.
The Directorate for Religious Affairs, which controls all the mosques in Turkey, issued the sermon to be preached on Tuesday, the Anatolia news agency was quoted by The Associated Press as saying.
"Terrorism, violence and anarchy have nothing to do with Islam," the sermon reads, the agency said.
But the Reverend Ian Sherwood, the British consulate chaplain in Istanbul, said he was "appalled" that he had not received any statement from a Muslim teacher to express sorrow or reconciliation, AP added.
The attack on the consulate and bank were the second within a week in Istanbul. Earlier, two simultaneous bombs on synagogues had killed 25 Turks, six of whom were Jews.
1,000 possible sleeper terror cells
Turkey's security forces are discussing a list of about 1,000 people they fear could be involved in sleeper terror cells.
The Turkish National Security Council was discussing the list Saturday as residents wondered if its biggest city would suffer more terror attacks.
Some on the list are Turkish but most of them are other nationalities who have had experience in countries such as Afghanistan, Chechnya and Bosnia.
Thousands of demonstrators took to the streets of Istanbul and Ankara Saturday in protest at the attacks. But union and non-governmental organizers criticized left-wingers of hijacking the marches.
Some banners read anti-U.S. and anti-Israeli messages.
Turkish officials are continuing to question a number of people arrested in connection with Thursday's attacks. (Full story)
Two more claims of responsibility have been for the bombing -- one from a person and one by a group, both claiming to represent Osama bin Laden's al Qaeda terrorist network.
In Washington, the U.S. State Department reissued its Worldwide Caution warning Americans they may be the targets of terrorist actions outside the United States.
Relatives comfort Eray, a son of Aynur Erkoca, a woman employee of the HSBC bank killed in the blast
It also, for the first time, mentioned al Qaeda specifically, instead of only talking about "terrorist groups."
"We are seeing increasing indications that al Qaeda is preparing to strike U.S. interests abroad. Al Qaeda and its associated organizations have struck in the Middle East in Riyadh, Saudi Arabia, and in Europe in Istanbul, Turkey," the caution said.
Jewish and Christian sites in Istanbul were given additional security, as was other high profile U.S. and British sites.
Israeli security sources, in an assessment of Saturday's synagogue bombings, said it is clear Turkey is a target because of its secular government and its ties to Europe, which terrorists are likely to target in the future.
Britain, the United States and Australia -- allies in the Iraq war -- have warned their citizens against non-essential visits to Turkey amid concerns of further attacks. (Warning of more attacks in Turkey)