(CNN) -- More than 20,000 people have been displaced by fighting between Buddhists and Rohingya Muslims in western Myanmar that saw Islamic organizations canceling the religious holiday of Eid al-Adha, a U.N. official said Sunday.
That estimate came from Ashok Nigam, the U.N. humanitarian coordinator for Myanmar. It follows clashes between the two sectarian groups that have left at least 64 people dead and thousands of homes torched in the western state of Rakhine.
The fighting came as the All Myanmar Islam Association, a collaboration of five major Islamic organizations, canceled celebrations for Eid al-Adha, a four-day holiday observed by many Muslims. The group gave no explanation for the move, but locals are seeing it as a precautionary measure after the violence in recent days.
There has been tension between the Buddhists and Rohingya Muslims since May, when violence began after three Muslim men were arrested on suspicion of raping and killing a Buddhist woman.
New satellite imagery obtained by Human Rights Watch shows what it said was extensive destruction of buildings in a predominantly Rohingya area of the coastal town of Kyauk Pyu. The swath of arson, the group said, stretched over 35 acres and included houseboats and floating barges.
The government in Myanmar "urgently needs to provide security for the Rohingya ... who are under vicious attack," said Phil Robertson, deputy Asia director of Human Rights Watch. "Unless the authorities also start addressing the root causes of the violence, it is only likely to get worse."
The Rohingya are a stateless Muslim minority who say they have been persecuted by the Myanmar military during its decades of authoritarian rule. Myanmar doesn't recognize them as citizens.
Unrest between the Rohingya and majority Buddhists has tested President Thein Sein's administration, which is trying to seek reconciliation with Myanmar's different ethnic groups and move the country toward more democratic governance.
The government has sent extra security into the troubled region and declared a state of emergency. The president's office warned Thursday that "manipulators" behind the violence can expect to be found and prosecuted.
Opposition leader Aung San Suu Kyi, speaking in Parliament on Friday, called for a greater security presence and urged authorities to investigate suspected human rights offenses.
CNN's Kocha Olarn and Paul Armstrong contributed to this report.