Kampala, May 9 : Uganda on Saturday was hit by a nationwide power blackout due to a fault that the country's state-owned power transmission agency say it was investigating. Uganda Electricity Transmission Company Limited (UETCL) said in a tweet: "We have lost transmission across the nation which has caused a nationwide blackout, please bear with us as we investigate the cause and work on restoration," Xinhua news agency reported. The blackout came hours before the start of an announced emergency power outage to allow water release testing at the country's Nalubale, Kiira, Bujagali and Isimba generation plants. The three-day outage which kicked off on Saturday will be effected during the daytime. Uganda on April 14 experienced a nationwide power blackout after floating weeds, measuring about 12 acres, disturbed the Nalubale power plant in the eastern district of Jinja. Uganda Electricity Generation Company Limited, another state-owned agency, said the Saturday morning outage was not because of floating weeds, but something else they were alsoinvestigating. Uganda is currently facing the rising water levels of Lake Victoria, which on Thursday hit a 50-year record high of 13.42 meters. /IANS