Soldiers and police are patrolling streets in western Myanmar where Buddhist mobs attacked offices and residences of aid workers this week, prompting the evacuation of non-essential staff.

Residents said Friday that a 13-year-old girl was killed Wednesday when police fired into the air to disperse the crowds.

The government said it would investigate the violence in Sittwe, the capital of Rakhine state. The attacks added to tensions there ahead of a national census that begins Sunday.

Though considered crucial to the development of the predominantly Buddhist nation as it emerges from a half-century of military rule, the census has strained ethnic rifts that have left up to 280 people dead and sent another 240,000 fleeing their homes since 2012. Most of the victims are from the long-persecuted Rohingya Muslim community.