PESHAWAR At least seven soldiers including a junior commissioned officer embraced martyrdom and 16 others sustained critical injuries when they were attacked by militants near Miranshah, North Waziristan Agency, on Friday. Sources informed that the convoy of the security forces was heading towards Datha Khail area from Miranshah when militants targeted it. The sources further informed that four military vehicles were also destroyed in the attack. AFP adds: Dozens of insurgents on Thursday attacked the troops in North Waziristan. Two officers were among the dead in the ambush in Datha Khail, a Taliban stronghold and recent target of US drone missile strikes, about 20 kilometres from North Waziristans main town Miranshah. It was a pre-planned attack. Dozens of militants first fired several rockets and then used other weapons and guns, an intelligence official based in Miranshah said, adding that four military vehicles were destroyed. A military statement said the convoy was on a routine mission from Miranshah to Datha khail, adding: Seven soldiers embraced shahadat (martyrdom), including an officer and a junior commissioned officer, while 16 soldiers were injured. Another security official in Miranshah said a lengthy gunbattle erupted after the ambush, but the Taliban fighters managed to flee. Militants attacked the convoy from three sides. Troops retaliated and an exchange of fire continued for several hours, he told AFP. The rugged tribal belt has become a stronghold for hundreds of extremists who fled neighbouring Afghanistan after the US-led invasion in late 2001. The same area where the troops were killed Thursday was the target of a US missile strike on April 12 which killed at least five militants.