DAMASCUS — An upsurge of intense fighting around Aleppo has killed scores of Syrians in the past weeks, displaced thousands and cut water and power to up to two million people on both sides of the front line, worsening the already dire conditions faced by hundreds of thousands in the city.

In a war already marked by a humanitarian crisis, the United Nations says the fighting threatens to replicate the deprivation recently suffered by those in rebel-held eastern districts of Aleppo among civilians living in the government-held west.

Residents and aid groups contacted by Reuters spoke of acute water shortages and power cuts, and concerns over food supplies and hygiene in a stark assessment of life in the city of Aleppo.

Advances by warring sides in the last month, which resulted in a siege of rebel-held neighborhoods and the severing of a major route into government areas of control, have choked off supplies and raised fears of the encirclement of the entire civilian population.

Syria’s largest city pre-war has been divided into government and rebel areas of control for much of the conflict, and has been the focus of escalating violence since a ceasefire brokered by Washington and Moscow in February crumbled. Its capture would be a major prize for President Bashar al-Assad.

Russia’s intervention last year helped turn the war in Assad’s favor. His forces, with the help of Lebanese Hezbollah and Iranian fighters, surrounded the eastern, opposition-held neighborhoods in Aleppo in July.

The latest major gains were made by rebels, however, who broke the month-long government siege in an attack last week on a Syrian military complex and also cut the main supply route to the western, government-held areas of the city.

Rebel forces bombarded the district of Hamdaniya on Wednesday. They killed more than a dozen people, the Syrian Observatory for Human Rights monitoring group said. Syrian and Russian warplanes have heavily raided the areas taken by insurgents.

The British-based group said bombardments by both sides have killed more than 120 people in the city since the start of August.