Suicide gunmen and car bombers attacked a government complex housing offices of Pakistan's top intelligence agency Wednesday, sparking a shootout that killed seven people, officials said.
The dead included five attackers, one intelligence agent and a government employee in what was an unprecedented attack in the otherwise sleepy southern town of Sukkur.
Although there was no immediate claim of responsibility, it is likely to revive fears that the reach of Islamist militancy is spreading in the nuclear-armed state of 180 million.
State TV said at least 38 people were wounded in what has been one of the bloodiest attacks blamed on Islamist militants in Pakistan so far during the holy Muslim fasting month of Ramadan.
Police said the attackers stormed the complex of offices and homes for senior officials, including from the Inter-Services Intelligence (ISI) agency, as people broke their fast after sundown.
They detonated two bombs -- first outside a police building and a car bomb outside the ISI office in the town, more than 1,000 kilometres (600 miles) south of the capital Islamabad.
A police official said apparently a suicide bomber first blew himself up in front of a police building and then a second suicide bomber detonated the explosive laden car outside the ISI office.
"Armed people have attacked. Apparently it is an organised terrorist attack, we have sent a heavy contingent of police to the site," Javed Odho, a Sukkur police officer, told AFP by telephone.
A hospital official told AFP that the bodies of an ISI agent and another government employee had been brought into the morgue, and that 15 other people had been admitted with injuries.
The ISI has been a frequent target for the country's Taliban movement as it wages a domestic insurgency, although Sukkur has traditionally been immune from such violence.
"A total of seven people were killed and several injured," said Major General Rizwan Akhtar, head of the paramilitary force, Sindh Rangers.
"The dead included three attackers, two suicide bombers and two others," he added.
"It was ISI headquarters which was attacked. The gate and front walls have been blown away," he said.
An intelligence official in Karachi, the capital of southern Sindh province, told AFP that the attackers detonated a bomb near the office of a senior police official and then a car bomb at the ISI office.
"One suicide bomber detonated an explosive laden car in front of ISI office and other militants started firing on police," Masood Bangash, a senior police official in Sukkur told AFP by telephone.
The ISI is Pakistan's most powerful spy agency, which has been attacked several times in the past by Islamist militants.
In May 2009, a suicide attack outside a police building next to the local ISI headquarters in the eastern city of Lahore killed 24 people.
In November that year a powerful car bomb ripped through ISI's headquarters in the northwestern city of Peshawar, killing 10 people and destroying part of the fortified building.
A month later in the central city of Multan two suicide attackers fired at soldiers while driving a truck bomb past security checkpoints in an attempt to approach the local office of the ISI.
Prime Minister Nawaz Sharif has strongly condemned the attack, which he said resulted in the "loss of precious human lives and injured many".
A hospital official in Sukkur told AFP that two dead bodies and 15 injured were brought to his hospital.
"Both of them are government officials, one is an employee of ISI and second from commissioner office," the official said.