In the days after the military in Myanmar seized power on Feb. 1 last year, millions of people took to the streets to oppose the takeover, walking off their jobs in what has become an enduring nationwide civil disobedience movement and resisting the junta’s murderous violence.

One year later, the Southeast Asian nation is mired in conflict, the economy is crippled, warfare has spread to every region, and public institutions are in a state of collapse. Peaceful protesters have been gunned down, suspects have been tortured, and thousands of civilians have been killed.

The initial daily protests, loud and colorful, have been replaced by an eerie quiet.

To mark the anniversary of the coup, protest leaders have called for a “silent strike” on Tuesday, urging people to stay home, close their shops and halt outdoor activity for six hours. The junta circulated leaflets warning that participants would be charged with terrorism, incitement and violating the electronic communications law. Dozens have already been arrested.

The regime has engendered such hatred that it has been unable to consolidate control. Hundreds of armed rebel units have sprung up across the country and a shadow National Unity Government — headed in part by ousted elected officials — has formed to help lead opposition to the junta.

“Since the early days of the coup, when protests were concentrated in the cities, the conflict has spread to the rest of the country,” said Khu Ree Du, a spokesman for the Karenni Nationalities Defense Force, one of many armed groups fighting the military. “The shape of the conflict will be more intense in the coming year because what the Myanmar military has done is unforgivable.”

As part of the coup, the military arrested more than 100 elected officials, including the country’s top civilian leader, Daw Aung San Suu Kyi, 76. She faces as much as 173 years in prison on 17 charges that her supporters say are trumped up. She has been convicted on five counts so far.

But Senior Gen. Min Aung Hlaing, the army commander in chief and leader of the coup, appears to have underestimated public contempt for him and his generals, who have responded with a vicious crackdown.

Junta forces have killed at least 1,500 civilians who were targeted at peaceful protests or in raids on homes and business, according to the United Nations Human Rights Office. Nearly a fifth of the deaths — at least 290 — occurred while the victims were in custody and often resulted from torture, the Human Rights Office said.

Thousands more civilians have died in remote areas during the military’s attacks on towns and villages, at times using heavy weapons, artillery and airstrikes. More than 8,800 opponents of the regime have been imprisoned.

“The Myanmar military has used extreme force and airstrikes in many areas,” said Padoh Saw Hla Htun, spokesman for the Karen National Union, another ethnic group seeking autonomy. “They target civilians. Now they are waging war on the whole country and trying to rule the people with fear. The military has turned Myanmar into a failed state within a year.”

In a statement on Monday, President Biden denounced the regime’s “unspeakable violence against civilians, including children,” and its denial of humanitarian access to millions who need lifesaving aid.

Addressing Myanmar’s people, Mr. Biden said: “We have not forgotten your struggle. And we will continue to support your valiant determination to bring democracy and the rule of law to your country.”

For decades, the military has battled numerous ethnic groups in Myanmar but has never gained complete control over areas on the country’s northern periphery. Now, fighting has reached every part of the country, and in some areas, newly formed anti-regime units are fighting alongside armed ethnic groups.

In recent months, the junta has lost control over even more territory, including in Chin and Rakhine states, the Sagaing region and the Magway division. In a recording leaked to local news media, a security minister in the Magway region told junta officials last week that the army had lost control of half a dozen districts in the region. He blamed the rebels’ popular support and their effective use of guerrilla tactics.

“As you all know, a government must be able to enforce its authority on the people,” said the official, Col. Kyaw Kyaw Lin.

Yanghee Lee, a former United Nations Special Rapporteur on Myanmar, called the military’s ouster of the civilian government a failed coup because the regime had not been able to consolidate power. What the country is seeing now, she said, is a “nationwide democratic revolution.”

“Min Aung Hlaing tried to seize power over Myanmar on the 1st of February last year,” she said. “One year later, he has not succeeded. Why has he failed? Because the people of Myanmar resisted.”

With the military attacking civilian targets in the countryside, more than 400,000 people have fled their homes. The international aid group Save the Children reports that at least 150,000 children are among those displaced and that many are living in makeshift shelters in the jungle, where they are vulnerable to hunger and illness.

In the weeks after the coup, pro-democracy protesters pleaded for help from the international community. Many carried signs reading, “R2P,” or “Responsibility to Protect,” referring to a 2005 United Nations doctrine affirming the responsibility of nations to shield populations from egregious crimes.

But they were soon disappointed.

The United Nations Security Council, which includes Myanmar allies Russia and China, has taken no steps to intervene. And the Association of Southeast Asian Nations, which counts Myanmar as a member, has been ineffective in stopping the violence.

Human rights groups have urged the international community to cut the supply of arms reaching the military, eliminate the flow of cash to the regime and end the junta’s impunity by prosecuting the generals in the International Criminal Court.

In January, the oil giants Chevron and Total yielded to pressure and announced plans to withdraw from a natural gas field off the coast of Myanmar, a major source of cash for the regime. But U.S. sanctions on military leaders have not proved to be a significant deterrent.

On Monday, Britain, Canada and the United States added new sanctions against top judicial officials and other individuals helping the junta, including U Jonathan Kyaw Thaung, the scion of a prominent business family.

“How many more people does Myanmar’s military have to detain, torture and shoot,” said Brad Adams, Asia director of Human Rights Watch, “before influential governments act to cut off the junta from its flow of money and arms?”