ISLAMABAD: Pakistan's military Saturday said it deeply regretted civilian casualties caused during a strike on a compound in a restive tribal area in which eight militants were killed.

An unspecified number of civilians were also reportedly killed Friday in a "targeted strike" on a militant compound in Orakzai, one of seven lawless northwestern tribal districts, the military said in a statement.

"Eight terrorists were killed in a targeted strike at a compound in Orakzai agency on 25 December 2009. However, there are reports of collateral damage in the adjacent compound due to blast effect," it said.

"Military authorities have deeply regretted the loss of civilian lives," it added, without saying how many were killed or injured.

"Military authorities are in touch with relatives of those who embraced shahadat (martyrdom) in this incident and all possible help and compensation will be provided to the affected families," the statement said.

It added that militants used compounds inside civilian areas to avoid attacks by security forces, thereby endangering the lives of civilians.

It is rare that the military admits civilian casualties in military operations, despite demands by rights groups to probe such deaths.

It does provide information on the deaths of militants and soldiers but these cannot be verified by independent sources as the tribal areas are out of bounds for the media and rights groups.

Pakistani troops this year launched multiple operations across the tribal belt, but are under fierce US pressure to target not only the Pakistani Taliban but also groups that focus on attacking foreign troops in neighbouring Afghanistan.

About 30,000 troops poured into South Waziristan in mid-October to try and dismantle the strongholds of the Taliban leadership. Officials believe that many militants had fled towards Orakzai.

Prime Minister Yousuf Raza Gilani has said that Orakzai might be the focus of the next full-scale military assault, and the United Nations says about 40,000 civilians have already fled the area.

Pakistan is in the grip of a fierce insurgency led by Taliban militants, with at least 2,700 people killed since the rebellion escalated in July 2007.