At least 15 Rohingya refugees, including four children, drowned when the overcrowded boat they were in capsized off the coast of Bangladesh on Tuesday, according to the Bangladesh Coast Guard.

A Bangladesh Coast Guard official, Hamidul Islam, told Reuters that the boat was filled with people trying to leave camps near Cox’s Bazar, Bangladesh, where hundreds of thousands of refugees have been living since a scorched-earth ethnic cleansing campaign by Myanmar’s military in 2017.

“It was inhumane,” he said. “The boat was carrying roughly 130 people, while it had a capacity of 50.”

Coast Guard officials said that at least 40 people were still listed as missing.

More than 730,000 Rohingya, a predominantly Muslim ethnic group, have fled Myanmar to Bangladesh since a campaign of killing, rape and arson began against them in 2017. Though both governments have promised the refugees would imminently return to Myanmar, the promise has not been kept.