A car bomb near a church in the Pakistani city of Karachi has injured at least 11 people, police say.
Several vehicles were destroyed in the blast
The powerful blast happened shortly after police received an anonymous telephone warning that a bible society near the church would be targeted.
The explosion is the first attack on Pakistan's small Christian community for more than a year.
The BBC's Paul Anderson in Islamabad says it will re-awaken fears among them that they are once again targets.
Television footage of Thursday's blast near the Trinity Church in Karachi showed extensive damage to cars in the area, with twisted metal and shattered glass scattered over the street.
A local Christian leader said one of the church's walls was badly damaged.
Police said they had received a warning that the Pakistan Bible Society would be attacked.
Christians in Pakistan suffered a spate of attacks in 2002
When officers went to investigate, attackers drove by and threw a small explosive device, believed to be a firecracker, at them.
Several minutes later a bomb in a nearby parked car exploded.
At least two police officers were among the injured.
No one has claimed responsibility for Thursday's blast and the assailants are believed to have escaped.
In mainly Muslim Pakistan there are about 3.8 million Christians, about 2.5% of the national population.
They have been targets of violence before, although the last incident was more than a year ago.
In 2002, six attacks on Christian targets left more than 40 people dead. The
most vicious was at a Christian society in Karachi, when gunmen tied up seven people and shot them execution-style.
The killings prompted calls for better security and protection at Christian buildings.
Most of the attacks were blamed on Islamic militants angry at Pakistan's support for the United States-led war against international terrorism.