Authorities in Nigeria's Zamfara state have declared a curfew and shut markets after violence marred the return of hundreds of kidnapped schoolgirls to their families, a state spokesman said Thursday.

Late on Wednesday, gunshots and chaos erupted during what should have been the joyous return of 279 schoolgirls abducted by gunmen from their boarding school last week. The government secured the release of the girls on Tuesday, but they had been undergoing medical checks and treatment. At least three people were shot, but it was not clear by whom.

A Reuters witness saw police firing tear gas at a group of protesters outside the school, and soldiers shooting into the air, after impatient parents burst in and grabbed their children to take them home. Zamfara state spokesman Sulaiman Tunau Anka called it "unfortunate civil disobedience" and said the governor had imposed a dusk-to-dawn curfew in the town, Jangebe, to prevent a further breach of the peace.

Anka also said market activities would be suspended until further notice, as authorities had uncovered "strong evidence" that these activities had aided and abetted bandits. He did not elaborate.

"The state government is poised to ensure safety of lives and properties of its citizens at all cost," Anka said. Earlier this week, President Muhammadu Buhari ordered a massive military deployment to Zamfara, banned mining and imposed a no-fly zone in the state.

The Jangebe abduction was the third mass school kidnapping in northern Nigeria since December. The kidnappings for ransom are the latest manifestation of years of festering banditry that has rendered large swathes of northwest Nigeria lawless.