Sri Lanka's armed forces were ordered on Tuesday to shoot at any persons damaging public property or threatening lives, Defence Ministry spokesman Nalin Herath said.
The island nation has been rocked by a bout of violence that has left at least eight people dead and 200 injured amid its worst economic crisis in history.
Sri Lanka has been suffering its worst economic crisis in history, with a severe shortage of foreign exchange stalling essential imports, including drugs and fuel, reports UNB.
For months, its tottering economy has been largely supported by India, which has provided assistance of more than $3.5 billion as the country began much-delayed talks with the International Monetary Fund (IMF) for a rescue package and also sought help from China.
China and India have long jostled for influence over Sri Lanka, a strategically located island situated off the southern tip of India with a population of 22 million people.
But the public's patience ran out on Monday after ruling party supporters attacked an anti-government protest camp in the commercial capital Colombo, triggering a bout of clashes in which eight people died and more than 200 were injured.
Hours after the violence erupted, Prime Minister Mahinda Rajapaksa resigned in the hope of forming a unity government and the police imposed a nationwide curfew until 7am on Wednesday. The country's Cabinet stepped down.
Protesters angered by persistent shortages of fuel, cooking gas and electricity defied the curfew to attack government figures, setting ablaze homes, shops and businesses belonging to ruling party lawmakers and provincial politicians.