Islamist militants killed six Pakistani soldiers in an exchange of fire with the military in a northwestern tribal district bordering Afghanistan, the army said on May 4.
An army statement said the gunbattle took place in North Waziristan, which has long been a hotbed of militants operating on both sides of the border.
The statement said three militants were killed and two were injured during the clash.
The outlawed Pakistani Taliban, also known as Tehrik-e Taliban Pakistan (TTP), an umbrella group of several Sunni militant groups, claimed responsibility.
The TTP claimed its fighters first targeted a military vehicle with a bomb, killing four soldiers, then shot at the remaining soldiers.
Prime Minister Shehbaz Sharif expressed condolences to the grieved families.
"No matter how long the battle, our valiant armed forces, with the support of the nation, will root out terrorism in its entirety," he said in a statement.
The bloodshed comes after Pakistan declared a new offensive against militants following a resurgence of attacks, including a mosque bombing that killed more than 100 people in February.
The militants have been increasing their attacks in some areas, including in the northern province of Khyber Pakhtunkhwa.
Local residents, political parties, and councils have repeatedly protested against the insecurity and called on the government to increase safety.
The government and the military have stressed that the security department is conducting regular operations against insurgents and has achieved success in recent years.
Pakistani military spokesman General Ahmad Sharif Chaudhry last month told a news conference that this year there have been 8,269 small and large-scale operations against the militants. The result was 157 suspected terrorists killed and 1,378 arrested. He said 137 soldiers were killed and 117 wounded in clashes with militants during the operations.