(Updates death toll, edits)
By Asim Tanveer
MULTAN, July 24 (Reuters) - Militants detonated four bombs in a heavily guarded Pakistani intelligence compound in the town of Sukkur on Wednesday and then fought security services, killing seven people and wounding at least 40, police officials said.
It was unclear who had carried out the attack, but previous similar operations have always been claimed by the Islamist Taliban, who appear to be throwing down the gauntlet to the new government of Nawaz Sharif.
A gun battle raged for more than an hour as security services pursued up to 10 militants, said Masood Bangash, deputy superintendent of police in Sukkur.
The city headquarters of the Pakistani military intelligence service, Inter-Services Intelligence (ISI), seemed to be the main target, police Deputy Inspector General Javeed Odho said.
A security official said five attackers had been killed along with a civilian and an ISI employee.
An attack of such intensity on a high-profile and supposedly secure target is the latest of series of demonstrations of militants' ability to strike at Pakistan's centres of power.
It also raises questions about the new government's aim of starting talks with militant groups.
Sharif pledged to seek negotiations and reconciliation with militant groups who were willing to talk before he won last May's election. But the attacks have increased since he took office, and his government has yet to present a security strategy.
Last year militants attacked Kamra, a major airbase, and damaged an aircraft.
The year before, Taliban gunmen attacked a naval base in Pakistan's biggest city, Karachi. Ten military personnel were killed in the 16-hour assault.
In 2009, they attacked the army's national headquarters in the garrison city of Rawalpindi. (Additional reporting by Mehreen Zahra-Malik; Writing by Katharine Houreld; Editing by Alison Williams and Kevin Liffey)