Five people were killed and around 40 inmates escaped when Taliban militants staged a jailbreak in north-western Pakistan, a news report said early Tuesday.
Two policemen were among those killed during the attack on the central prison in Dera Ismail Khan district of Khyber-Pakhtunkhwa province, during which more than 25 explosions were heard, Dawn newspaper reported online.
The Taliban claimed responsibility, saying 100 militants participated including several suicide bombers, the report said, citing the spokesman for the Tehrik-i-Taliban group, Shahidullah Shahid, dpa reported.
A police official said Monday more than a dozen militants first hurled grenades to break the outer security ring and then engaged the security forces with gunfire.
The clashes were continuing, the province's inspector general for jails Khalid Abbas was quoted as saying by the Dawn report, published online early Tuesday.
The prison was one of the province's safest, Abbas said, but was designed to hold criminals, not terrorists and militants.
Dera Ismail Khan is adjacent to South Waziristan, a tribal district near the Afghan border under the control of Pakistani Taliban.
A prison department official said Monday around 250 of more than 5,000 inmates held at the central prison in Dera Ismail Khan belong to terrorist organizations including the Taliban.
The Dawn report said at least 45 were high-profile militants, according to intelligence reports.
The attack came as parliamentarians prepared to vote for a new president Tuesday.
Islamist militants have stepped up their activities across Pakistan since a new government took office in early June.