Live Updates: Bangladesh’s Prime Minister Has Resigned, Army Says

The student-led protests grew into a broader movement seeking the removal of Ms. Hasina, who was seen as an increasingly authoritarian leader. On Sunday, the deadliest day of the protests, almost 100 people were reported killed in clashes between security forces and demonstrators across Bangladesh.

Ms. Hasina, one of the world’s longest ruling female leaders, had blamed the violence on her political opponents and called for “resisting anarchists with iron hands.”

Here’s what you need to know:

Ms. Hasina played a pivotal role in the politics of Bangladesh, a nation of around 170 million people that proclaimed its independence in 1971. She won re-election to a fourth consecutive term in January. She is the daughter of Sheikh Mujibur Rahman, the country’s charismatic founding leader, who was killed in 1975 in a military coup when Ms. Hasina was 28. She served as prime minister from 1996 to 2001 and regained power in 2009.

Under her leadership, the economy, boosted by investment in the garment export industry, saw rapid growth, and average income levels at one point surpassed those in neighboring India. Bangladesh also saw rapid development in education, heath, female participation in the labor force and preparedness against climate disasters including flooding — a national priority in a delta nation.

But her critics said that she tried to turn the country into a one-party state, and the protests that began last month reflected broader discontent against her rule.

Large numbers of protesters have entered the official residence of Prime Minister Sheikh Hasina in Dhaka, footage on local television channels shows. She appears to be on her way out of the country, with diplomatic sources saying she has been spotted at an airport in Dhaka.

It has been before. Bangladesh’s army has a history of staging coups and counter coups. But over the past couple decades, the military has taken a less overt role in public affairs, choosing more often to exercise influence from behind the scenes.

Part of that shift as been attributed to Ms. Hasina. Her father, Bangladesh’s first leader, Sheikh Mujibur Rahman, as well as much of her family, was killed in a deadly military coup in 1975. In her time in office, she has stacked its leadership ranks with loyalists, and allowed them access to lucrative government contracts and other businesses.

There are international incentives for the military, as well, which has been a major contributor to United Nations peacekeeping missions that have given it another important side business. Any involvement in a coup would subject the army to criticism — or ostracism — from the U.N., whose human rights chief responded to the recent killings by calling for restraint and accountability from those with “command responsibility.”

While the army was deployed on the streets during the crackdown to clear the protesters late last month, there have been reports of discomfort in the ranks over it. Dozens of former senior officers also issued a statement calling on the military not “to rescue those who have created this current situation” — a statement seen by some as referring to the police and paramilitaries, and possibly even to Sheikh Hasina herself.

On Sunday, the army’s chief, Gen. Waker-uz-Zaman, gathered senior officers for a meeting that was seen as an attempt to allay concerns. In a statement after the meeting, the army said its chief had reiterated that “the Bangladesh Army will always stand by the people in the interest of the public and in any need of the state.”

If Ms. Hasina’s power becomes untenable, analysts said the army would be unlikely to opt for a takeover. It might, though, try to aid some transition period from the sidelines with a caretaker government — something that happened in 2007.

“There are major international ramifications to a military coup. And more than leaders it is the younger officers who are hesitant to go ahead with anything of the sort,” M. N. Khan, a retired general of the Bangladeshi Army, said.

The exact number of deaths on Sunday was unclear, but it appeared to be the deadliest day since the protests began in July. At least 13 of the dead were police officers, the country’s Police Headquarters said in a statement.

Over the weekend, the tensions flared into the kind of localized clashes across the country that appeared difficult to contain. With the public already angry at the police forces, seeing them as an overzealous extension of Prime Minister Sheikh Hasina’s entrenched authority, attention focused on Bangladesh’s powerful military.

Ms. Hasina has worked to bring the military to heel. But it has a history of staging coups and was being watched for how it positions itself in the escalating crisis.

Here’s what we know about the deadly crackdown on Sunday.

Shayeza Walid contributed reporting from Dhaka.

More than 200 people have been killed. After a curfew and communication blackout eased, the revival of the protests over the weekend, in addition to a call by Ms. Hasina’s party for its own supporters to take to the streets, plunged Bangladesh into a particularly dangerous phase.

On Monday, the army chief announced the resignation and said an interim government would be formed.

Here’s what to know about the protests.

What were the protests about?

Students at the University of Dhaka, the country’s top institution, started the demonstrations on July 1, and they later spread to other elite universities, and then to the general public. The protests turned violent when some members of student wing of the governing party, the Awami League, began attacking the protesters.

Besides sending the police and paramilitaries into the streets, the government locked down schools and colleges. Officials said they slowed down internet connectivity to stop the spread of rumors and protect citizens, making it harder for protesters to organize and make plans via social media platforms.

The protests were initially about coveted government jobs and who is entitled to them. An old quota system, reinstated recently by the courts, reserves more than half of those jobs for various groups, including the families of those who fought for independence from Pakistan. The students said that the system is unfair and that most of the positions should be filled based on merit.

In the past few weeks, however, the movement grew massively and become centered on calling for accountability for Ms. Hasina’s increasingly harsh governance.

How did the protests evolve?

The crackdown in late July, which saw over 200 people killed and 10,000 arrested, temporarily dispersed the protesters. However, the large number of deaths also fueled protesters’ anger.

Over the weekend, the tensions spread away from protests and into clashes across the country that appeared difficult to contain. On Saturday at a rally of tens of thousands, protesters called for the resignation of Ms. Hasina, who has been in power for the past 15 years.

In response, Ms. Hasina’s Awami League party called on its supporters to join counter protests, and she asked the country’s people “to curb anarchists with iron hands.”

The threat emboldened protesters, who called for a march on her residence in central Dhaka on Monday. The government once again imposed a curfew, effectively shutting the country down.

By midafternoon Monday in Dhaka, what appeared to be conditions for another deadly day of protests had eased. Police officers let protesters cross barricades into the center of the city, and the army said they would make a statement.

Shortly after, the army chief announced that Ms. Hasina had left the country.

What will happen to Bangladesh after her ouster?

Ms. Hasina was among the world’s longest-serving female heads of government, a secular Muslim who fought Islamic militancy, helped lift millions out of poverty and deftly kept both India and China at her side.

Over the past 15 years, Ms. Hasina entrenched her authority and divided Bangladesh, a nation of 170 million people. Those who were loyal were rewarded with patronage, power and impunity. Dissenters were met with crackdowns, endless legal entanglement and imprisonment.

The army has tapped the president, who holds a ceremonial role, to form a new government. Bangladesh’s army has a history of staging coups and counter coups. But over the past couple decades, the military has taken a less overt role in public affairs, choosing more often to exercise influence from behind the scenes.