At least 12 persons were killed and several injured as heavy rain continued to lash Pakistan's southern port city of Karachi.Torrential rain coupled with gusty winds hit the city late Wednesday. Seven out of the 12 victims died from electrocution and others in roof and wall collapse incidents in different parts of the city, Xinhua news agency cited local media reports as saying.Several grid stations tripped disrupting electricity supply to many areas in the city while a majority of the schools remained closed. Road and rail services were also affected by the heavy rainfall, causing inconvenience to a large number of people planning to go to their home towns for the upcoming festival of Eid-ul-Adha, ARY News reported.According to the Pakistan Meteorological Department, thundershowers with moderate to heavy rainfall may occur in the city in the next 24 hours. The weather office also advised fishermen to take precautionary measures and not to venture into the deep sea till Saturday.This is the second wet spell which hit the country over the past 10 days. At least 22 people were killed and several injured in the wet spell on August 20.