Russian jets bombed areas near the northwestern Syrian city of Idlib on Sunday, witnesses and rebel sources said, marking a new year flare-up for the last opposition-held bastion, writes Reuters.

War planes flying at high altitude, which tracking centres said were Russian Sukhoi jets, dropped bombs on several towns and a main water pumping station serving the overcrowded city of Idlib, whose wider population is more than a million.

No immediate comment was available from Russia or the Syrian army, which says it targets the hideouts of militant groups who control the region but deny any attacks on civilians.

An official at the city’s water utility service said it was out of action as a result of the strikes.

A senior U.N. official who confirmed the water station was “badly damaged” in an air strike said such attacks worsened the humanitarian plight of millions of displaced Syrians.