according to the United Nations . NEW : Homs chemical weapon inspectors will investigate millions 'confidential ' locations in Wadi Aldahab . Homs says the death toll may rise . The blast occurred in the Wadi Aldahab neighborhood in Syrian Observatory for Human Rights , the group says . It says the explosion happened after shells fell on pro-regime parts of the city .
NEW : Homs chemical weapon inspectors will investigate millions 'confidential ' locations in Wadi Aldahab . Homs says the death toll may rise . The blast occurred in the Wadi Aldahab neighborhood in Syrian Observatory for Human Rights , the group says . It says the explosion happened after shells fell on pro-regime parts of the city .