KARACHI: A series of blasts rocked the southern town of Sukkur late Wednesday as militants rammed an explosive-laden vehicle into a compound of Pakistan’s premier intelligence agency, security officials said.

At least nine people were killed, including five attackers and four agency officials in what was an unprecedented attack in the otherwise peaceful town.

Police said the attackers detonated two bombs — one outside a police building and a car bomb outside the ISI office in the town, located around 500 kilometres from Karachi, the main city of Sindh province.

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-filled car outside the ISI office.

The terrorists had seized control of one government building, sparking a shoot-out between the militants and security forces in the high-security Barrage Colony area.

The exact number of casualties was still unclear as TV channels put the death toll between seven to ten but there was no confirmation from the hospital.

Sources told Dawn that four agency officials were among the dead including ISI's deputy director Maj Zeeshan, Azizullah, Asghar Ali and Nazeer Ahmed. There was no official confirmation of the death of the agency officials.

Major General Rizwan Akhtar, head of the paramilitary force, Sindh Rangers said that all attackers had been killed and the ISI compound had been cleared of the militants.

“All three militants who seized the compound have also been killed and the building completely cleared of terrorists,” said Akhtar.

He said the front wall and gate of the ISI office had been blown away by the impact of the first blast.

A senior police official said it appeared to be “an organised terrorist attack". Militants have launched such sophisticated attacks before, but Sukkur has been traditionally immune from such violence.

No group has claimed responsibility for the attack so far.

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.

In another elaborately planned attack last year, militants attacked Kamra, a major airbase, and damaged an aircraft.

The year before, Pakistani Taliban gunmen attacked a naval base in Karachi, the country’s biggest city. Ten military personnel were killed in the 16-hour assault.

In 2009, they attacked the national army headquarters in the garrison town of Rawalpindi, close to the federal capital.

Prime Minister Nawaz Sharif has strongly condemned the attack, which he said resulted in the “loss of precious human lives and injured many”.

—DawnNews correspondent Asif Mehmood contributed to reporting.