Russian-backed Syrian government forces on Tuesday retook from the Islamic State (IS) militant group a pumping station that supplies water to second city Aleppo, a monitoring group said.
"Regime forces took over the area of Al-Khafsa and seized the water-pumping station after the withdrawal of the IS ," said Rami Abdel Rahman of the Syrian Observatory for Human Rights.
The Islamist militants fled in the face of a Syrian government offensive backed by Russian air strikes, he said.
The Al-Khafsah pumping station provides the water supply for Aleppo and residents of the government-held city had been without mains supplies for some 50 days since the Islamist militants cut it.
The government offensive in Aleppo province has involved heavy air strikes and shelling and prompted an exodus of civilians.
The United Nations says at least 26,000 people have fled since February 25.
Many have headed towards the town of Manbij and surrounding villages, which are held by a US-backed Kurdish-Arab alliance known as the Syrian Democratic Forces.
Early Tuesday, the Observatory reported that government forces were very close to the pumping station and the Jarrah military airport.
For now, the airport remains in the hands of the Islamist militants, who seized the facility in January 2014 from rebels who had taken it from the government in February 2013.