Pakistani security forces, backed by helicopter gunships and artillery, killed 26 Islamist fighters in Mohmand tribal region today, a paramilitary official with knowledge of the operation said.
Many militants fled to Mohmand after being driven out of Bajaur, a neighbouring tribal region where security forces had mounted an offensive more than six months ago.
Security forces pounded militant positions on Saturday after they came under fire during a search operation in Mohmand's Saapri area.
"Twenty-six militants were killed and many were wounded," the paramilitary official said. There was no independent confirmation.
Security analysts have said a suicide attack on mosque that killed at least 37 people in the neighbouring Khyber tribal region yesterday might have been carried out in retaliation for the operation in Mohmand province.
The Pakistan army has fought to contain an Islamist militant insurgency that has spread across the northwest during the past two years.
US President Barack Obama said yesterdy that al-Qaeda and Taliban militants had to be rooted out from Pakistani tribal lands as part of a new strategy to stabilise Afghanistan, and reduce the threat of an al-Qaeda attack in the West.
Afghan president Hamid Karzai said today he is in "full agreement" with the US review of strategy on Afghanistan and Pakistan and said the plan to include Iran in a regional role was a "positive thing".
"It is exactly what the Afghan people were hoping for," Mr Karzai said of the review.
The new strategy comes with violence in Afghanistan at its highest level since US-led forces ousted the Taliban in 2001.
The insurgents, often operating from safe havens in the border regions of Pakistan, have escalated their attacks, with violence spreading from the south and east to the outskirts of the capital, Kabul.
Mr Karzai has often criticised Pakistan for not doing enough to fight the Taliban and al-Qaeda cells on its own side of the border, causing tension between the two countries.