New arrivals said they had fled killings and the burning of their homes in northern Rakhine state, according to reports from the UN Refugee Agency (UNHCR).
Many of the new arrivals are Rohingya Muslims who had walked for up to 14 days, carrying their children and whatever they could pack at short notice.
“We’re back in a situation of full alert as far as influxes are concerned. It is a big increase to see 11,000,” UNHCR spokesman Adrian Edwards said.
“We have had big numbers coming across by the day in the six weeks of this emergency, so we’re approaching some of those peak levels,” Edwards said.
There were reportedly half a million plus in just six weeks into Bangladesh, and a situation that has potential to worsen, he added.
The violence that sparked the exodus began in August, after Rohingya militants attacked police posts in northern Rakhine, prompting military reprisals by the government.