(CNN) -- A state of emergency in Myanmar was put in place to stop "attempts by a small number of people to spread ... violence to other parts of the country," President Thein Sein said Thursday.
In his first speech since making the emergency declaration last week in response to clashes between Buddhists and Muslims, he accused "instigators" of escalating a private dispute into sectarian violence that killed at least 40 people last week.
"We did not resort to the use of force immediately mainly because we do not want any possible endangerment of our ongoing democratic transition and reform efforts," the president said. "That said, I am firmly committed to use the power vested in me by the constitution to deploy our security forces and to use existing laws to prevent and protect the life, liberty and security of my fellow citizens."
The president said some were exploiting the situation to engineer violence in other parts of the country.
"I would like to warn all political opportunists and religious extremists who try to exploit the noble teachings of these religions and have tried to plant hatred among people of different faiths for their own self-interest: Their efforts will not be tolerated," he said.
During the clashes in Meiktila, which were reportedly set off by a dispute between a Muslim gold shop owner and two Buddhist sellers, rioters set fire to houses, schools and mosques, prompting thousands of residents to flee their homes.
The government declared a state of emergency in the city Friday, allowing the military to help reinstate order. But as the situation there appeared to calm, authorities reported arson attacks by groups of Buddhists in other towns in the region over the weekend.
One group, the Myanmar Islamic Religious Organization, blamed the government for the loss of lives.
"It is analyzed that loss of Muslims' lives and properties, mosques and religious schools in this way are due to weakness and omission of administrative authorities to provide protection and take action effectively," the organization said in a statement.
The unrest highlights the fragility of ethnic relations in Myanmar, also known as Burma, as it emerges from decades of military repression. Authorities have released thousands of political prisoners and pursued peace talks with rebel groups in the past two years.
The clashes in Meiktila and elsewhere have drawn expressions of concern from U.N. and U.S. officials.
The sudden boiling over of tensions between Buddhists and Muslims in central Myanmar follows sectarian troubles that killed scores of people in the western part of the country last year.
Those clashes, in Rakhine state, took place between the Buddhist majority and the Rohingya, a stateless ethnic Muslim group.
CNN's Jethro Mullen contributed to this report.