By Gul Yousafzai
QUETTA, Pakistan (Reuters) - At least 13 people were shot dead by gunmen in a suspected sectarian attack on a passenger bus in Pakistan's southwestern Baluchistan province on Tuesday, the second such attack in just over two weeks.
The attackers, who were said by police to have arrived in a pickup truck, intercepted the bus on the outskirts of the provincial capital of Quetta. Five people were wounded.
"After intercepting the bus, four to five gunmen went in to the bus and opened fire and then fled," senior police Hamid Shakeel told Reuters.
The bus was carrying mostly Shi'ite Muslims from the Hazara community, who were returning from Quetta.
One of the wounded men, Hussain, however told Reuters from the hospital that about 45 minutes outside of Quetta, two men already on the bus ordered the driver to stop and started shooting.
Ten people were killed on the spot while three died at a hospital. There were about 20 people on the bus.
The wounded were driven to a hospital in the brightly painted bus, where protesters enraged by the attack, set it on fire after it was emptied of passengers, according to Geo TV, a private Pakistani television channel.
Video from the scene showed the bus with bullet holes in the front windshield, smoke pouring out of its sides and dozens of men milling around.
"Our government, our law enforcement agencies have left us at the mercy of these barbarians," Abdul Khaliq, a leader of the Hazara Democratic Party, told Geo television.
Sunni Muslims militants loyal to al Qaeda and the Taliban regularly carry out attacks on members of Pakistan's Shi'ite minority. They have stepped up attacks in recent months.
A similar attack on September 20 killed at least 26 Shi'ite pilgrims in Mastung district while they were on their way to Iran.
No one claimed responsibility for Tuesday's attack.
Pakistan has seen a surge in violence since al Qaeda chief Osama bin Laden was killed by U.S. special forces in a secret raid in a Pakistani town in May.
Militants have vowed revenge for bin Laden's death.
Sunni and Shi'ite Muslims have a rivalry going back almost 1,400 years, when Islam split over the successor to the Prophet Mohammad.
(Reporting by Gul Yousafzai and Naseer Ahmed; Writing by Augustine Anthony; Editing by Chris Allbritton and Ed Lane)