Mumbai: Two persons were killed and 11 injured after a four-storeyed building collapsed partially in south Mumbai today morning. The rear portion of 'Wood Up' building in Dongri collapsed at 8.30 am leading to the casualties, fire-brigade said.The injured have been taken to nearby hospitals and six fire-engines, two earthmovers, four ambulances and two dumpers have been rushed to the spot for rescue operations. The rescue personnel are currently looking if there would be any more persons trapped in the debris.