At least seven people, including schoolteachers, have been killed in two separate shooting incidents in northwestern Pakistan near the border with Afghanistan.

District police chief Muhammad Imran told RFE/RL that both incidents took place on May 4 in the Kurram district of the province of Khyber Pakhtunkhwa.

The first shooting occurred around 1 p.m. local time when unknown assailants attacked a vehicle, killing one person.

The incident enraged people in the area, and they entered a school in which they believed people belonging to opposing sectarian groups were working as teachers. They opened fire, killing six people including four teachers, Imran said.

The police chief said that the people killed in the school were residents of different areas of Kurram.

The first person killed in the attack on the vehicle was a Sunni Muslim, while those shot in the second attack at the school were Shi'ite Muslims, a regional commissioner, Saiful Islam, told Reuters.

Based on preliminary information, both incidents are due to sectarian disputes between tribes over land and forests, but Imran said that the investigation is ongoing. The situation is under control, he said.

"It is not clear whether the second incident was a reaction to the first one," Islam said, adding that security has been heightened in an area already tense due to sectarian violence.

The violence occurred on the same day that Islamist militants killed six Pakistani soldiers in an exchange of fire with the military. An army statement said three militants were killed and two were injured during the clash in North Waziristan, which borders Kurram to the south.

The outlawed Pakistani Taliban, also known as Tehrik-e Taliban Pakistan (TTP), an umbrella group of several Sunni militant groups, claimed responsibility.

Khyber Pakhtunkhwa Province has long been a hotbed of militants operating on both sides of the border.

With reporting by Reuters