Cary — Cary investigators said they believe a cigarette sparked a fire that damaged some condominiums in Cary late Thursday.

No one was injured, but two units in the Wellington Ridge neighborhood off Cary Parkway were heavily damaged.

Firefighters said the blaze started in or near the back patio of a top-floor unit. They said they believe the fire was accidental.

The fire displaced residents in three other units when electricity was cut off.

All residents were staying with family members or friends, authorities said.