Video clues to Turkey bombers
At least 23 killed, more than 300 hurt in coordinated attacks
Turkish police search the rubble and debris for clues in the bombing near the Neva Shalom.
Turkish authorities say two bombs which killed 23 people weighed about 400 pounds each.
ISTANBUL, Turkey (CNN) -- Security tapes shot from cameras mounted outside two Istanbul synagogues showed men driving slowly by the places of worship shortly before their vehicles exploded, killing at least 23 people, a high-level Turkish security officer said.
The bombers were among the 23 dead. More than 300 were also wounded in Saturday's attacks, the officer said.
Speaking to CNN Turk, the officer also said that tissue samples taken from a body found in the wreckage of one blast matched samples found on the steering wheel of the vehicle used in that attack.
Four men detained and questioned by Turkish authorities were released, he said, although officials had called them suspects.
Intelligence analysts on Sunday discounted two claims of responsibility made on behalf of the al Qaeda terrorist network for the weekend bombings and last week's attack on Italian troops in Iraq, pointing to a history of similar dubious claims.
The London-based Arabic newspaper al Quds al Arabiya said it received claims of responsibility in those attacks from the Abu Hafs al Masri Brigade, which claims to be affiliated with al Qaeda.
The group has claimed responsibility for other incidents in the past, including the August blackouts in the eastern United States and Canada, a bombing outside an Indonesian hotel and the attack on the U.N. headquarters compound in Baghdad the same month.
The second claim went to the Saudi-owned magazine Al Majalah. In it, Abu Mohamed Al Ablaj -- who claims to lead training camps of Al Mujahideen in al Qaeda -- took responsibility for the same attacks.
Al Ablaj also has claimed responsibility on behalf of al Qaeda for last weekend's attack in the Saudi capital Riyadh and for the August blackouts in North America.
Coalition intelligence sources say they have not had a chance to assess the reliability of the most recent claims. Independent analysts note that both sources have made dubious claims in the past.
After cutting short a visit to northern Cyprus, Turkish Prime Minister Recep Tayyip Erdogan toured the bombing site at Neve Shalom Sunday afternoon, accompanied by Foreign Minister Abdullah Gul. Edrogan said the Turkish government would provide some form of compensation for those who suffered losses.
Israeli Foreign Minister Silvan Shalom traveled from Jerusalem to pay his respects to the victims, who include at least six Jews. He visited the American Hospital, where 78 of the wounded were being treated, including the son of Turkey's chief rabbi, who suffered minor injuries.
Saturday's near-simultaneous bombings rocked Neve Shalom and Beth Israel and their busy neighborhoods as Jewish worshippers prayed at Sabbath services. On Sunday, four were in critical condition, officials said.
Authorities speculated that the attacks may have been carried out by terrorists from outside the country.
Turkish Gul described the blasts as "a terror attack which has international links."
But Turkish Interior Minister Abdulkadir Aksu said it was too soon to tell. Investigators are "considering every possibility," he said. "Any organization could be behind this."
Earlier, members of the Turkish news media reported a claim of responsibility for the blasts from a radical Turkish Islamist group, the Islamic Great Eastern Raiders Front.
Officials credited tight security around the buildings for keeping the bombers from inflicting more damage inside the synagogues. Many of the casualties were passers-by.
Police investigators said the 300- to 400-kg (660- to 880-lb) bombs were made of ammonium sulfate and nitrate mixed with fuel oil.
Vehicles were small trucks
A top security officer told CNN Turk that the security tapes showed that both vehicles were small trucks. One was purchased at an Istanbul auto lot 35 days before the blasts, he said, by a man who paid 300 million Turkish lira (slightly more than U.S.$200) in cash for the vehicle.
The tags on the truck were fake, police said.
Witnesses told police a red pickup truck parked in front of a shop across from Neve Shalom on a narrow street the Kuledibi district. A shop staffer approached the driver and told him he could not park there. The driver had gotten out of the car to talk to the employee when it detonated, carving a 2 meter (7 feet) deep crater in the street.
Security at Neve Shalom has been high since 1986, when gunmen burst into the synagogue and sprayed the congregation with gunfire during Sabbath services, killing 22 people. The attack was blamed on a Palestinian militant group. And, because of terrorist fears, synagogues throughout Europe have been heavily fortified over the years.
The second car bomb detonated near Istanbul's Beth Israel Synagogue, about 5 kilometers (3 miles) away, in the Sisli district. The bombing at the rear of the building caused structural damage and started fires, which were swiftly extinguished.
Turkey's Jewish community numbers about 25,000, in the predominantly Muslim country of 68 million. Avi Alkas, Istanbul's Jewish community leader, called the blasts "a severe blow to our community".
There is no tradition of anti-Semitism in Turkey, which has long been home to a vibrant Jewish community.
"We have always proved Islam and Judaism can live harmoniously in a peaceful manner, in a co-existence," Alkas said. "I do presume that these are coming from outside, not within the country."
IIsrael and the United States offered to assist Turkey. Other nations, including France, Britain and Greece, decried the bombings.
-- Journalist Andrew Finkel and CNN Turk's Kaya Heyse and Dicle Buharali in Istanbul, CNN Producers Henry Schuster and Caroline Faraj, Correspondents Sheila MacVicar and Chris Burns and Producer Yoav Appel in Jerusalem, and White House Correspondent Suzanne Malveaux and Producer Elise Labott in Washington contributed to this report.