TAIZ, Yemen >> The familiar thud of shelling echoed off the mountains that cradle this besieged and ravaged city. For a few terrifying minutes, a warplane circled over neighborhoods and humming afternoon markets before dropping a bomb that momentarily silenced the guns.

But the fighting never stops for long in Taiz, or across Yemen for that matter, a country that has endured 14 months of shattering civil war.

Yemen’s government and its main opponents, the Houthi rebels, have been negotiating for weeks to end the conflict, under intense pressure from the United States and from other Western nations alarmed that al-Qaida’s local affiliate, al-Qaida in the Arabian Peninsula, is gaining recruits, weapons and money in the midst of the country’s collapse.

A frenzied escalation of violence over the last few days is threatening a nationwide cease-fire that was supposed to build confidence for the talks. The bloodshed has laid bare the furious rivalries — between aging warlords, tribes, Islamist groups and regional powers — that are making Yemen’s hostilities almost impossible to stop.

Even if the negotiations somehow succeed, Yemenis scarred by the vicious fighting, past broken promises and deepening divisions say they fear that any truce would just be a prelude to an even uglier war, fought between regions, religious sects — even neighbors.

“People have feelings of revenge,” said Mohamed Nagy, whose house is on a hill less than a mile from one of the front lines in Taiz, a city that residents boasted was a beacon of culture and intellectual life in Yemen before it was transformed into one of the country’s deadliest battlefields.

“The reconstruction of souls, by both sides, will take a long time,” Nagy said.

The disagreements extend to who started the conflict. Fighting began in early 2015, when the Houthis drove Yemen’s government, led by President Abed Rabbo Mansour Hadi, from Sanaa, the capital. The crisis quickly escalated into a multisided war.

A Saudi-led military coalition is bombing the Houthis, a Shiite-led movement that the Saudis claim is in league with Iran. Military units loyal to Yemen’s deposed autocratic leader, Ali Abdullah Saleh, Hadi’s predecessor, are fighting alongside the Houthis. Other factions in the country, including southern separatists, powerful tribes and Islamist groups, have also taken sides.

The United States is becoming more deeply involved in the fighting. The Obama administration has provided military support and intelligence to the Saudi-led coalition, and in the past few weeks, it has sent Special Operations forces to Yemen to fight al-Qaida.

Al-Qaida in the Arabian Peninsula faced little resistance from the Saudi-led coalition for most of the war. The militants held territory across southern Yemen until the United Arab Emirates recently launched an offensive to dislodge them.

Negotiations to end the conflict in Yemen started only after tens of thousands of people had been killed or injured and millions displaced from their homes. The front lines have also hardened, sketching violent new borders on Yemen’s map.

The most vexing and polarizing battle has been for Taiz, one of the country’s largest cities and a strategic gateway between northern and southern Yemen. The Houthis and their pro-Saleh allies have encircled the city for a year, fighting a coalition of mostly local groups, including ultraconservative Sunni groups and al-Qaida fighters, known collectively as the resistance.

Various cease-fire initiatives have repeatedly failed to separate the warring parties. The nature of the confrontation — with both sides accused of carrying out atrocities against civilians — has served as a dire warning about the perils facing Yemen as the war drags on.

The Houthis and pro-Saleh forces have shelled neighborhoods from their positions in the hills and on the city’s outskirts, while severely limiting the flow of essential goods, including medicines, to the city. Resistance snipers have shot civilians in Houthi-controlled areas and carried out summary killings and kidnappings, according to human rights workers in Taiz.

Houthi officials recently allowed reporters a rare visit to Taiz, but only to a section that they controlled, called Houban. The visible damage there, mostly from airstrikes, is spare, compared with the city center. But the trauma — among the people who fled the shelling to find shelter in the yards of benevolent landlords, or the medical workers tending to the conflict’s victims while still haunted by the destruction of their own homes — was unmistakable.

Hisham Maged, a nurse working in a hospital in Houban operated by Doctors Without Borders, said most of his friends had fled the city or been killed.

“Some died in their homes,” he said, “Some in the street.”

As he tallied the destruction to Taiz, an ancient city vanishing under artillery shelling and airstrikes, he singled out the damage to a library, a particularly pointless target of the war.

“It is so strange, so dangerous,” he said.

Many said it would take international peacekeepers to separate the combatants. Politics was hampering any solution, as well as the proliferation of armed groups, said Bashir Fadel, a driver with Doctors Without Borders.

“To go back to normal will take a long time,” he said. “There are weapons everywhere — guns, with young and old.”

Yemen’s violence stretches from the southern port city of Aden, where shadowy militant groups have carried out assassinations and bombings, to Yemen’s northern border with Saudi Arabia, the site of repeated clashes between the Houthis and Saudi troops.

Sanaa, controlled by the Houthis, endured months of airstrikes that have subsided for now. But the planes from the Saudi-led coalition still hover, testing the nerves of residents and sending them scurrying fearfully around the city these days.

The residents of Sanaa do not lack for reminders of the raids.

Caved-in buildings, like the home of the judge who was killed in an airstrike along with at least six members of his family, are preserved like shrines, with armed guards standing outside ready to narrate the tragic tales.

Lampposts are decorated with posters in shades of green, depicting the conflict’s martyrs, some children, some soldiers, the names too numerous to count.

Displaced people clog Sanaa’s traffic intersections, jostling with vendors of window wipers or sesame cakes and asking passing drivers, and sometimes even one another, to spare some change.

Everyone is bruised by the war.

Abdelsalam Ali, a student at Sanaa University, said fighting had destroyed his house in Taiz several months ago. A sister was injured and is still hospitalized, he said. His father had a heart attack when the house was hit. “It took him 40 years to build,” Ali said.

“We have to cling to a little bit of hope,” he said of the possibility of a peace deal.

But his friend, Maknoun Ali, disagreed: “The Yemeni elites are taking charge. It will be the same conflict. They are fighting for their own interests, and not for the nation.”

The Houthis’ days as rulers of Sanaa may be numbered if negotiations to form an interim government succeed. But like Sanaa’s residents, the rebels are moving frantically, to ensure their legacy and their continued survival.

To rally their followers, they have blanketed Sanaa with portraits of the group’s founder, Hussein Badreddin al-Houthi, with a zeal that has brought derision even from members. Houthi leaders extol their — arguably Pyrrhic — victory: the survival of the movement after a withering bombing campaign by the Saudi-led coalition that was among the deadliest and most indiscriminate in the region’s recent history, causing a majority of the more than 6,000 civilian deaths during the war.

As the rebels send text messages to the public appealing for money, the young men they mobilized for the war dismiss talk of peace deals. Mohamed Khalid al-Sokkari, 19, said he had recently returned from fighting against the Yemeni government and its allies in Marib province, east of the capital, branding his opponents as “Al-Qaida, mercenaries and other traitors of the nation.”

The other side was responsible for breaches of the cease-fire, he said, adding, “We won’t reach a deal with them.”

The war, he said, “has yet to start.”

© 2016 The New York Times Company