At least 60 labourers, including some women, were injured when a concrete bridge collapsed in Upper Assam's Dhemaji district. Condition of 17 persons is stated to be serious.Official sources said the mishap occurred on Friday when a heavy vehicle was trying to cross the bridge between the construction site of Bogibeel road-cum-rail bridge at Silapathar. The labourers were carrying on repair work at the site of the accident.Most of them have been shifted to Silapathar public health centre while those seriously hurt are being treated at the Dhemaji civil hospital.