Burma's President Thein Sein declared a state of emergency on Sunday after at least 17 died in sectarian riots that spread to several towns in western Burma. The violence is the largest challenge faced by Thein Sein since he announced plans to bring in democratic reforms after 50 years of military rule.

The conflict began late last month after three Muslim men were accused of raping and killing a Buddhist girl in Rakhine state, where long-simmering sectarian tensions have now boiled over into violence on both sides of the ethnic divide. More than 400 homes have been burned in the rioting, and violence is now spreading to other parts of the country.

Burma has seen an upsurge in protest since rules on public gatherings were loosened several months ago, and this may have contributed to the rapid spread of the current crisis. The regime's response has been harsh, with security forces reportedly firing into a crowd of people in at least one case, and imposing dusk-to-dawn curfews throughout the region.

Learn more: Why is this happening now? Al-Jazeera has the best analysis this morning of the deeper reasons behind this conflict.

Sources: Wall St Journal, Reuters, Avaaz