Police in central Sri Lanka maintained a curfew a day after the killing of an anti-government activist drew international condemnation.

On Wednesday, the administration agreed to investigate charges that police used excessive force to disperse protesters throughout the island who were protesting high fuel prices and calling for President Gotabaya Rajapaksa's resignation amid the deteriorating economic crisis.

Sri Lanka is experiencing its worst economic crisis since 1948, with frequent blackouts, chronic shortages of petrol and other essentials, and record inflation wreaking havoc.

"I have already initiated an investigation into the officers' conduct at Rambukkana," police commissioner Chandana Wickramaratne said on Wednesday as he issued an indefinite curfew in the area.

According to a previous police statement, a mob was preparing to set fire to a diesel tanker when authorities opened fire to disperse them in Rambukkana, 95 kilometers (60 miles) east of the city.

At least 29 people were injured, including 11 police officers, in the first fatal fight since anti-government demonstrations erupted earlier this month.

"Deeply distressed following the Rambukkana tragedy," Rajapaksa tweeted on Wednesday. "I am confident that a thorough, unbiased investigation will be conducted."

Envoys based in Colombo, including those from the United Kingdom, Canada, and the United States, voiced alarm about the police shooting and urged all parties to exercise patience as Sri Lanka prepares to begin bailout negotiations with the International Monetary Fund Washington, DC.

"A thorough, transparent investigation is critical, as is the protection of the public's right to peaceful protest," US Ambassador Julie Chung said.

"I condemn all forms of violence and call for restraint," British High Commissioner Sarah Hulton continued.

And David McKinnon, her Canadian colleague, stated that "those who incite violence must be held accountable."

Within hours of the shooting in Rambukkana, police shot tear gas to disperse another protest in the island's south. Still, officials and villagers said there were no immediate reports of casualties.

Residents stated police were sent in to remove crowds occupying the main route and obstructing traffic in Matara, 160 kilometers (100 miles) south of Colombo.

Protests occurred around the country in response to a dramatic increase in fuel prices and a lack of diesel and petrol. The government seeks three to four billion dollars from the IMF to resolve its balance-of-payments issue and replenish depleted reserves.

Sri Lankans have faced months of shortages of essential commodities such as food, cooking gas, fuel, and medicine, queuing for hours to purchase minimal supplies.

Recently, fuel prices have increased multiple times, resulting in significant increases in transportation costs and other requirements. This week, there was another round of increases.

Since April 9, thousands of protesters in the capital Colombo have occupied the president's beachside office entrance, demanding that the leader resign.

Rajapaksa acknowledged widespread outrage over the governing family's mismanagement on Monday, a day after selecting a new government to quell the crisis's fury.

Sri Lanka's economic collapse occurred due to the coronavirus pandemic, which decimated essential revenue from tourism and remittances. Thet announced last week that it would default on massive foreign debt.