ISLAMABAD, Pakistan — The violence that's engulfing Pakistan lurched in a sectarian direction Thursday as an apparent suicide bomber targeted a gathering of Shiite Muslims in the northwestern city of Peshawar, leaving nine people dead and 25 injured.
Witnesses said the assailant — who appeared to be a teenager — entered a prayer hall, opened fire with a gun, then blew himself up.
The attack came during the Shiites' month of mourning, known as Muharram, which in recent years has seen heightened sectarian tensions. The rites climax this weekend, when Shiites gather for large processions that wind through crowded city centers, making them an easy target for attacks.
The assailant somehow circumvented strict security measures that the government had put in place for the mourning period, with worshipers frisked and sent through metal detectors before being allowed to enter Shiite prayer halls.
It was the third major bombing since the assassination Dec. 27 of former Prime Minister Benazir Bhutto. Blasts in Lahore and Karachi have claimed dozens of victims.
Pakistan is reeling from a spate of suicide bombings that accelerated after troops stormed the Red Mosque in Islamabad last July and ousted the Sunni Muslim hardliners who occupied it. Thursday's Peshawar bombing was the first to aim at the minority Shiite community, which could signal a new direction for the militants.
Shiites make up 20 to 25 percent of Pakistan's 160 million people, probably the second biggest Shiite community after Iran. Aside from violent attacks by extremist groups on both sides, Sunni and Shiite communities in Pakistan largely have been able to live peacefully together.
Pakistan was last hit by large-scale sectarian violence in the mid- and late 1990s, when there were tit-for-tat attacks on Sunni and Shiite gatherings. At the time, it was thought that the two groups were backed by Sunni Saudi Arabia and Shiite Iran, which were fighting a proxy war on Pakistani soil.
During the holy month of Muharram, Shiites show their grief for the seventh-century death of the Prophet Muhammad's grandson, Imam Hussein, an event that led to the split in Islam between the Shiite and Sunni sects.
Sectarian Sunni groups also have joined with jihadist forces that emerged in the 1980s to fight Soviet occupying troops in Afghanistan. The government has blamed the modern Taliban and al Qaida version of these fighters for the bombings in Pakistan in recent months.
Farzana Shaikh, an associate fellow at the Royal Institute of International Affairs in London, said the latest violence was "very troubling. Until today I was prepared to accept that the hideous sectarian violence seen in the past had declined."
Close to Peshawar, in the semi-autonomous tribal belt, Taliban militiamen have attacked and killed Shiite villagers in the Kurram area in recent weeks, leading thousands to flee.
(Shah is a McClatchy special correspondent. Tim Johnson contributed to this article from Islamabad.)