The Syrian regime and its ally Russia have for nearly four months ramped up bombardment of the last major opposition bastion in the country after eight years of brutal conflict.
The strikes pummelling the northwestern Idlib region have claimed some 820 civilian lives since late April, according to the Britain-based Syrian Observatory for Human Rights war monitor.
The United Nations says more than 400,000 people have been displaced.
Here is some background.
– Jihadist stronghold –
Regime and Russian strikes pick up after the powerful Hayat Tahrir al-Sham (HTS) jihadist alliance, led by Syria‘s former Al-Qaeda affiliate, takes control of the area in January 2019.
A major escalation begins in late April, after clashes and strikes since February had already killed around 200 civilians according to the UN.
Bordering rebel-backer Turkey, the region under HTS control covers nearly all of Idlib province and parts of neighbouring Aleppo, Hama and Latakia provinces. It hosts some three million people.
– Escalation –
On April 26, Russia and the regime’s other main ally Iran pledge along with rebel backer Turkey to cooperate to “ultimately eliminate” HTS.
After Russian raids on April 26-27 kill around 15 civilians, the UN warns Moscow to abide by its commitment to “avoid large-scale military offensives” on the region.
Russia denies targeting civilians.
– ‘Humanitarian catastrophe’ –
By early May the strikes have forced 150,000 people to flee and knocked 12 hospitals and 10 schools out of action, the UN says.
Britain, France, the United States and eight other countries at the UN Security Council warn on May 10 of a “potential humanitarian catastrophe”.
On May 17, Amnesty International accuses the regime and Russia of a “deliberate and systematic assault” on hospitals.
– Banned weapons –
The US says on May 22 there are indications the Syrian government used chemical weapons in Idlib. France says it has similar information. Neither offer up proof.
On June 3, Human Rights Watch accuses the regime and Russia of using “internationally banned” weapons in attacks on civilians.
They include cluster munitions and large air-dropped barrel bombs, it says.
– No let up –
On May 22, regime air strikes kill 23 civilians. Dozens more die in days of bombardment over the last week of that month.
A new flare-up kicks off on June 15 when at least 45 people are killed, including 10 civilians. Five days later regime bombardment kills another 20 civilians.
Strikes on July 21 kill 18 civilians, among them a young citizen journalist Anas al-Dyab, who was a member of the White Helmets rescue group and also contributed to AFP.
The following day, regime and Russian air strikes kill 50 people, many at a vegetable market in Maaret al-Numan.
– Inching closer –
The regime resumes military operations against the region on August 5, scrapping a ceasefire reached days earlier.
The Syrian army accuses jihadists of launching rockets on the Hmeimim air base west of the bastion, causing “great human and material losses” nearby.
On August 11 the regime seizes the town of Al-Habeet on the edge of Idlib, after a deadly battle that leaves more than 130 fighters dead.
Regime fighters push further into Idlib on August 14, inching towards the key town Khan Sheikhun, lying on a highway coveted by the regime.
Jihadists down a regime plane and take the pilot prisoner, a first since the escalation in late April according to the Observatory.