The attackers opened fire on Monday as they forced themselves into the headquarters of the frontier constabulary in Peshawar city before blowing themselves up inside the complex, police said.
Three paramilitary personnel were killed, said Javed Iqbal, the deputy commandant of the force.
"The first suicide bomber carried out an attack on the main entrance of the constabulary and the others entered the compound," a senior official told Reuters on condition of anonymity as he is not authorised to speak to the media.
"Law enforcement personnel, including the army and police, have cordoned off the area and are carefully handling the situation as we suspect there are some terrorists inside the headquarters," the official added.
The headquarters of the force is located in a densely populated area of Peshawar, the capital of Khyber Pakhtunkhwa province.
"The road has been closed for traffic and cordoned off by the army, police and (security) personnel," Safdar Khan, a resident of the area, told Reuters.
The five wounded people, including two paramilitary personnel, were taken to Lady Reading Hospital, its spokesperson Mohammad Asim said.
No militant group has claimed responsibility for the attack so far.
Islamist militants operating in the region have ramped up attacks in recent weeks after last month's deadly border clashes between Pakistan and Afghanistan.
Pakistan blames the Afghan Taliban for harbouring the militants who it says launch cross-border attacks, a charge Kabul denies.
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