Syrian opposition media say pro-government airstrikes have hit areas in Idlib city and the surrounding province, killing at least four people on Tuesday.
Barrel bombs were also dropped over Khan Sheikhoun, in south Idlib province, according to local media.
A video checked by the social media agency Storyful showed extensive damage. It has been shared by pro-opposition media and is described as showing damage from “Russian warplanes” hitting civilian houses in Idlib.
In the video graffiti is seen saying “Jund al-Aqsa” – a jihadist group affiliated with Fateh al-Sham, formerly linked to al-Qaeda, which is excluded from a ceasefire deal.
The UK-based Syrian Observatory for Human Rights reported that warplanes had hit areas in Idlib. Quoting local contacts, it spoke of airstrikes having caused explosions in areas near the Turkish border.
Reports over the past few days have said the ceasefire deal brokered by Russia and Turkey appeared to be holding.
Some have not been optimistic that it will last. In Idlib, a small crowd of anti-government demonstrators took to the streets to protest.
With Aleppo again under government control, there have been fears that the offensive could shift to Idlib, where many rebels and their families have been sent.