Myanmar President Thein Sein imposed martial law over parts of Myanmar last week following clashes between Muslims and Buddhists. Similar conflicts erupted last year in Rakhine in northern Myanmar.
The government extended a dusk-to-dawn curfew in Nattalin and Zigon, China's official Xinhua news agency reports. The government imposed curfews on three other towns this week.
Myanmar Senior Gen. Min Aung Hliang vowed Wednesday during a military parade that national security was need to ensure the country's reforms.
Myanmar earned praise for democratic reforms that began with general elections in 2010. Concerns over the status of political prisoners, human rights and religious violence have overshadowed those reforms.
Deputy Asia director for Human Rights Watch Phil Robertson said Myanmar's progress is in jeopardy unless the government can learn from last year's conflict in Rakhine.
"By failing to stop violence and prosecute those who incite it, the country's leaders are failing the test of reform," he said in a statement.