BEIRUT (AP) — Syrian government forces and insurgent groups exchanged shelling in northwestern Syria on Monday that killed at least 10 people dead, the vast majority of them in rebel-held areas, state media and opposition activists said.

The area has been witnessing acts of violence in recent weeks between government forces and insurgents on the edge of the last rebel stronghold in the northwestern province of Idlib.

The region had been relatively calm since a truce brokered in March last year by Turkey and Russia halted a crushing three-month Russian-backed government air and ground campaign that had killed hundreds and sent 1 million people fleeing toward the Turkish border.

Opposition activists say government forces fired dozens of artillery shells on the villages of Ihsim and Barah on the southern edge of Idlib killing nine people, according to the Britain-based Syrian Observatory for Human Rights, an opposition war monitoring group. It added that 13 people were wounded in Barah.

Idlib-based activist Taher al-Omar said the dead included a local commander of the al-Qaida linked Hayat Tahrir al-Sham, as well as several others fighters from another militant group. He added that three civilians were killed as well.

Insurgents in return shelled the government-held village of Joreen, killing a girl and wounding her father, said Syria's state news agency, SANA.

Syria's 10-year conflict has killed half a million people and displaced half the country's pre-war population of 23 million. They include 5 million who are refugees outside the country.