Fresh protests roiled Bangladesh on Saturday, just weeks after a deadly government crackdown, as demonstrators returned to the streets in what appeared to be the biggest numbers yet and escalated their demands to include the prime minister’s resignation.

In its efforts to break last month’s student-led protests, which started peacefully but turned violent after demonstrators were attacked, the government detained student organizers, rounded up about 10,000 people and accused tens of thousands more of crimes such as arson and vandalism.

A curfew and communications blackout quieted things down, and the students won a significant concession from the courts on their initial demand to end a preferential quota system for public-sector jobs.

But the crackdown by the security forces of Prime Minister Sheikh Hasina — which led to the deaths of more than 200 people — seems to have made many Bangladeshis even angrier and broadened the movement’s scope.

The protesters’ re-emergence on the streets, days after the curfew and communications blackout were eased, ratcheted up what was already the biggest challenge that the iron-fisted Ms. Hasina has faced in her 15 years as leader of this country of 170 million people.

As they gathered in huge numbers on Saturday, the demonstrators whittled their demands to a single — and highly provocative — request. Previously, they had called for an apology by Ms. Hasina and the firing of some officials. Now, they are demanding the resignation of both her and her government as accountability for the hundreds of protester deaths.