Sri Lanka will send troops to guard 100 key power transmission centers across the island nation, officials said Monday, a day after the worst power outage in 20 years, as the head of the state-owned utility board refused to rule out sabotage.

Sunday's crippling power cut, the second in as many weeks, lasted about eight hours, fueling public unhappiness over a perceived lack of action by President Maithripala Sirisena's government to avert sudden outages.

"We requested the president to provide military protection to these key positions and the president has assured us he will provide the required security," Power Minister Ranjith Siyambalapitiya told reporters in the capital, Colombo.