Five weeks after the mass exodus of Rohingyas from Myanmar began on 25 August, the UN says the total number of arrivals in Bangladesh has now topped 501,000.
It's just over a month since Myanmar's military launched what is widely reported to be a brutal campaign against minority Muslims living in Rakhine state, sparking what the United Nations has called ''a human rights nightmare''.
UN Secretary-General Antonio Guterres recounted ''bone-chilling accounts from those who fled, mainly women, children and the elderly'' in a speech before the UN Security Council on Thursday. Their testimonies, he said, ''point to excessive violence and serious violations of human rights''.
Myanmar has blocked all UN aid agencies from delivering urgently needed humanitarian supplies to Rohingya communities.
Myanmar's civil leader, Nobel laureate Aung San Suu Kyi, has so far said little to address the crisis, despite heated international pressure to do so.
Suu Kyi, who skipped the UN General Assembly this month, has also dismissed mounting allegations of state-sponsored atrocities against Rohingyas as ''misinformation''.
The Rohingya have extremely limited rights in Buddhist-majority Myanmar, and are classified as illegal immigrants rather than citizens. They have long suffered from state-sponsored discrimination and possible crimes against humanity.
But their plight rapidly and drastically worsened after 25 August, when Rohingya militants attacked government security posts. The military responded with extreme measures, prompting refugees to flee to neighbouring Bangladesh and creating ''the world's fastest developing refugee emergency,'' according to Guterres.
In the past month, human rights groups have reported rape, arson, killings and other forms of abuse against Rohingyas and their villages by state actors.
Desperate to escape by any means necessary, Rohingyas have fled Myanmar by land and sea, sometimes walking for several days without food.
On late Thursday, a boat carrying more than 60 Rohingyas capsized off the Bangladeshi coast. At least 23 are confirmed dead, including several babies. The rest are missing, unaccounted for or feared to have drowned.
This tragedy ''is a grim reminder of the extraordinary risks that desperate Rohingya are taking in order to escape the violence engulfing their homeland,'' said UNICEF Bangladesh representative Edouard Beigbeder. ''Dozens of others are believed to have perished making similar journeys'' since the crisis erupted, in late August he noted.
But Myanmar's national security adviser, U Thaung Tun, denied accusations of persecution against Rohingyas in an address to the Security Council on Thursday.
''I can assure you that the leaders of Myanmar, who have been struggling so long for freedom and human rights, will never espouse policy of genocide or ethnic cleansing and that the government will do everything to prevent it,'' he said. ''We are concerned by reports that thousands of people have crossed into Bangladesh. We would like to fathom the real reasons for the exodus.''