LAHORE, Pakistan -- Suicide bombers attacked police protecting marches by minority Shiite Muslims in Pakistan's two largest cities Tuesday, killing 12 people and wounding dozens, officials said.
The first and most deadly attack occurred in the eastern city of Lahore, where the bomber detonated his explosives as police tried to search him, killing 10 people. About an hour later, a second bomber struck in the southern port city of Karachi, killing at least two people.
The attacks laid bare the challenges facing Pakistani officials trying to secure cities far from the northwest, where militants fighting Pakistan's U.S.-allied government and American forces in neighboring Afghanistan have long thrived. Many recent attacks have targeted minority Muslim and other religious groups.
The Taliban claimed responsibility for the attack in Lahore, where thousands of Shiite worshippers were marking the end of a 40-day mourning period for the Islamic sect's most beloved saint when the blast hit their procession early Tuesday evening.
The bomber is believed to have been a young teenage boy who was wearing a suicide bomb jacket and also carrying a bag full of explosives, said senior police official Aslam Tareen. He detonated his explosives when police tried to search him, he said.
"It is a great sacrifice by the police officers who laid down their lives to protect innocent people," said Tareen.
Footage from the scene showed ambulances racing to the area and men carrying away victims. One young man whose arm was apparently hurt screamed as he was placed on a stretcher. A white car caught up in the explosion was largely destroyed, its hood twisted upward. A man lay wounded on the ground with two women and a child weeping beside him.
Dr. Zahid Pervaiz at the city's Mayo Hospital told reporters that 10 dead bodies had come in, while another 52 people were wounded.
Shakirullah Shakir, a spokesman for the Fidayeen-e-Islam wing of the Pakistani Taliban, told The Associated Press in a phone call that the militant group had dispatched the bomber and warned of more bombings.
Later Tuesday evening, a suicide bomber struck police protecting a group of people returning from a Shiite march in the Malir neighborhood of Karachi, Pakistan's largest city.
Three people were killed and three wounded in the attack, said Hamid Paryar, a doctor at Karachi's largest hospital. Two of those killed and one wounded were policemen, he said.
The third person killed is believed to be the suicide bomber, who was riding a motorcycle and carrying his explosives in a bag, said senior police official Shaukat Shah.
The blast occurred near a police van protecting the Shiite marchers, said Akbar Jaffry, who witnessed the bombing.
Attacks roughly tripled last year in Lahore and Karachi, according to a recent report by the Islamabad-based Pak Institute for Peace Studies.
The trend is a sign that militants are having greater success exporting the fight far from their northwest heartland along the Afghan border. The Pakistani army, under U.S. pressure, has carried out several offensives against militants in its northwest, but violence persists.