A U.S. soldier also was killed Friday in a grenade attack, raising to at least 22 the number of American troop deaths so far in May. That's the deadliest month for U.S. forces in Iraq since September, when 25 died.
The grenade detonated near a U.S. patrol in the northern province of Ninevah, the military said in a statement, providing no further details.
Insurgent activity has persisted in northern Iraq despite several U.S.-Iraqi military operations.
Friday's bus station bomb was attached to a car parked inside the station in the Shiite enclave of Khalis, according to local police and a report from the provincial security headquarters.
Police officers gave the casualty toll on condition of anonymity because they were not authorized to release the information.
The U.S. military said the attack occurred near a vegetable market, killing at least one person and wounding 14. Conflicting casualty tolls are common in the chaotic aftermath of bombings in Iraq.
Earlier Friday, a local leader of a government-backed Sunni paramilitary group was killed when a bomb hidden on a motorcycle exploded as he opened his butcher store on the outskirts of the Diyala provincial capital of Baqouba, police said.
The head of Baqouba's main group fighting al-Qaida in Iraq, Khalid Khudeir Mohammed, confirmed the death and said Khazal al-Sammaraie was the leader of a local chapter of the so-called Awakening Council.
Maj. Derrick Cheng, a spokesman for U.S. forces in northern Iraq, said the military had an initial report of at least five people wounded in the attack.
U.S. commanders say the Sunni groups have been pivotal in helping drive down the levels of violence in Iraq. But members have been frequently targeted as insurgents seek to derail security gains ahead of June 30 deadline for the Americans to withdraw from urban areas in Iraq.
Police also said a roadside bomb struck a civilian car late Thursday on a highway linking the towns of Khanaqin with Qara Tappah. The blast killed two boys ages 8 and 10 and their father, according to a provincial police report.
Diyala, an ethnically and religiously diverse province that borders Baghdad, and Mosul to the north are considered the main battlegrounds in U.S.-Iraqi efforts to solidify security gains. But attacks persist despite several crackdowns.
The U.S. military said Friday that 301 people have been detained and more than a dozen weapons caches discovered in the latest U.S.-Iraqi military operation in Diyala dubbed "Glad Tidings of Benevolence II," which began May 1.
He died Wednesday in Dahuk, 260 miles (430 kilometers) northwest of Baghdad, according to the Iraqi sports ministry said.
The coffin - covered with a bouquet and a portrait of Ammo Baba - was carried by mourners in a procession that included senior government and sports officials at Baghdad's Shaab stadium.
"Over more than half a century, Baba has given Iraq many sports accomplishments as a player, a coach and as a human being," Iraq's Shiite Vice President Adel Abdul-Mahdi said.
Dawud shot to football fame in Iraq after scoring the country's first goal in an international game in the 1957 Pan Arab games. He was named coach of the Iraqi national team in 1978 and lead Iraq to two Olympic Games, according to Iraqi sports officials.
Associated Press Writers Hamid Ahmed and Muhieddin Rashad contributed to this report.
(This version CORRECTS monthly US toll to 22 sted 21.)