The Syrian government and rebel factions seeking to topple it poured reinforcements into the besieged northern city of Aleppo on Monday, as both sides braced for a decisive battle that diplomats are trying to avert.
Monitors said as many as 2,000 pro-government fighters had arrived in the devastated city since late Sunday, prompting the head of the Britain-based Syrian Observatory for Human Rights, which monitors Syria's civil war, to warn that "the great battle of Aleppo" is, in a word, "imminent."
Separately, the government-leaning Syrian daily Al-Watan reported Monday that the army had received "the necessary military reinforcements" to retake areas of the ravaged city from which it retreated under heavy rebel fire Saturday.
Rebel militia, including al-Qaida-linked fighters, captured the eastern part of the city in 2012, and have battled to a stalemate against government forces for control of the city since then.
Monitors say as many as a half-million civilians remained trapped in the city, and at least 230 civilians are known to have been killed there in the past two weeks.
Russia, U.S. deal
The latest buildup comes as Russian Defense Minister Sergei Shoigu, speaking on Russian television, said Moscow and Washington are moving closer to a deal that could help ease the massive humanitarian crisis gripping the once vibrant city.
"Step by step we are nearing an arrangement ... exclusively about Aleppo, that would allow us to find common ground" that could bring peace to the territory, Shoigu said Monday.
In Washington, U.S. State Department spokeswoman Elizabeth Trudeau, responding to Shoigu's remarks, told reporters that U.S. and Russian envoys remain in close contact on the Aleppo crisis.
"We have seen the [Shoigu] reports and have nothing to announce," she said.
The multi-sided Syrian civil war pits the government forces of President Bashar al-Assad and his Russian allies against a loosely knit coalition of rebels seeking to drive Assad from power. That coalition includes al-Qaida-linked fighters, making Western governments reluctant to send arms to the rebels.
The third major party to the five-year-old conflict, the extremist Islamic State, is seeking to establish an Islamist "caliphate" in large swaths of Syria and neighboring Iraq. The group has used widely circulated videos to show its fighters slaughtering hundreds of civilians as it seeks to expand its rule.
Separately, the Syria Democratic Forces, formed in 2015 with U.S. support, has focused on driving IS fighters from strongholds along the Turkish border.
The United Nations estimates as many as 400,000 people have been killed, most of them civilians, since fighting first erupted near Damascus in 2011.