The team had been driving to a training camp in neighboring Jordan in May 2006, when their convoy was stopped and all 15 athletes abducted along a road between the cities of Fallujah and Ramadi, in Anbar province.
Also on Saturday, an explosion leveled a Sunni mosque Saturday in Basra, residents said, in the second retaliatory attack in as many days for the toppling of minarets at a prized Shiite shrine in Samarra.
Members of the Anbar Salvation Council, a group of Sunni tribal leaders who have partnered with U.S. and Iraqi officials to fight Al Qaeda influence in Anbar, found the 13 bodies Friday west of Ramadi, near the main highway leading to Jordan, said Anbar police Col. Rashid Nayef. Two of the athletes remained unaccounted for.
The remains — mostly skulls and bones entangled in tattered sports uniforms — were transferred to Imam Ali Hospital in Baghdad's predominantly Shiite Sadr City neighborhood, home to most of the athletes. A doctor there, who spoke on condition of anonymity for security reasons, said the bones would undergo DNA testing to determine their identities.
Relatives gathered at the hospital Saturday to mourn the victims. Women in black robes cried out while men hoisted rickety wood coffins atop minivans and cars. Plastic athletic sandals lay scattered on the ground near the bodies.
The athletes were members of a private sports club that hopes to one day send members to the Olympics.
"His dream was to represent his country in sports, but instead he was killed," said Ali Kanoun, cousin of one of the victims, Rasoul Salah.
"I tell the killers, you should point your guns at the Americans and the foreigners (fighting in Iraq) instead of hurting athletes who were representing all of Iraq, not their tribe or sect," Kanoun said by telephone from a crowd of mourners at Imam Ali Hospital.
Athletes and sports officials have increasingly become targets of threats, kidnappings and assassination attempts in Iraq, either as part of tit-for-tat violence between Shiites and Sunnis or for ransom.
Victims have included the Sunni head of one of Iraq's leading soccer clubs, an Iraqi international soccer referee, a top player on the Iraqi Olympic soccer team and a national volleyball player.
A blind Iraqi athlete and paralympics coach were kidnapped last year but later released unharmed after sports officials said their abductors determined neither man was linked to the Sunni insurgency.
Gunmen also kidnapped the chairman of Iraq's National Olympic Committee and at least 30 other officials last year, including the presidents of the tae kwon do and boxing federations, in a bold daylight raid on a sports conference in the heart of Baghdad. Iraq's national wrestling coach, a Sunni, was killed around the same time in a Shiite district of Baghdad.
Meanwhile, Iraqi police did not immediately respond to the bombing of the al-Ashrah al-Mubashra mosque, witnesses said, raising fears that the city's Shiite-dominated security forces were unwilling to stop sectarian attacks on Sunni landmarks.
Defense Secretary Robert Gates was in Baghdad, where a citywide curfew remained in place to prevent mosque attacks or other retaliatory violence. He was expected to press the Iraqi government to move more quickly toward political reconciliation and other vital reforms that many see as critical to gaining control of violence in the country.
Bombers loaded into pickup trucks pulled up to the al-Ashrah al-Mubashra mosque in Basra's al-Hakimiya district at dawn, residents in nearby houses said. Minutes after they left, a huge explosion tore through the building, leveling it completely.
It was unclear whether there were any guards present at the time, and why Iraqi security forces did not intervene. Witnesses said they saw no sign of any immediate response from police.
As they were leaving, the insurgents wrote graffiti on the mosque complex's outer wall with the names of revered Shiite saints, witnesses said. They also hoisted a green Shiite flag over a crumbling part of the mosque complex, they said.
Some nearby houses were damaged in the blast, but no injuries were reported.
Basra is Iraq's second-largest city, located 340 miles southeast of Baghdad.
On Friday, police said bombers posing as television cameramen destroyed another important Sunni mosque near Basra, the Talha Bin al-Zubair shrine. Afterward, Prime Minister Nouri al-Maliki ordered an indefinite curfew in Basra, which remained in effect Saturday.
The attacks were in apparent retaliation for the suspected Al Qaeda bombing of the Shiite Askariya shrine in Samarra three days earlier. Wednesday's explosions brought down the mosque's towering minarets and stoked panic that Iraq could fall further into a spiral of sectarian killings.
In February 2006, Sunni militants blew up the same shrine's glistening golden dome, in an attack whose aftermath has killed tens of thousands of Iraqis.
Meanwhile, radical cleric Muqtada al-Sadr called on Iraqi Shiites Saturday to gather next month at the Askariya shrine to show their commitment to their faith.
In a statement, al-Sadr said the pilgrimage to the shrine will climax July 7, which falls on the birthday of Fatima al-Zahraa, daughter of Islam's 7th century Prophet Muhammad and wife of Imam Ali, the founder of the Shiite faith.
"I hope the Sunnis of Iraq will be there waiting for you, paving the road with roses and basil leaves, opening their hearts and their homes to you," he said. "Let your pilgrimage be one of love, peace, security and unity ... go bearing olive branches and wearing shrouds."