Beirut: The northwestern Syrian province of Idlib is the last to remain mostly out of regime control after seven years of civil war.

It is to Idlib that the regime of Bashar Al Assad sends rebels or civilians evacuated from other opposition strongholds, retaken after devastating sieges.

The province is strategically important, sharing a border with rebel backer Turkey.

It is also adjacent to the coastal Syrian province of Latakia, a regime stronghold that is home to Al Assad’s clan.

Idlib city, the province’s capital, lies near the road linking Syria’s second city Aleppo to the capital Damascus.

The province counts 2.5 million inhabitants, including more than one million people displaced by fighting between the regime and rebels, or evacuated from areas recaptured by pro-regime forces.

Before fighting broke out, the majority of Idlib’s inhabitants worked in agriculture, mainly growing cotton and cereals, or commuted to the neighbouring province of Aleppo.

In March 2015, a coalition of Islamist rebel groups including Ahrar Al Sham and extremists from the Al Qaida-linked Al Nusra Front, now known as the Fatah Al Sham Front, seized the Sunni-majority city.

Syrian warplanes, and later Russian jets, have repeatedly targeted cities and towns across the province.

Idlib province has been hit by several suspected chemical attacks.

On April 4, 2017, a sarin gas attack hit the town of Khan Sheikhun, killing at least 83 people according to the United Nations. The Syrian Observatory for Human Rights said 87 died, including 30 children.

In October, the UN accused the regime of responsibility, a charge denied by Damascus.

In 2016, a UN commission found helicopters from two regime-controlled air bases had dropped chlorine-filled barrel bombs on at least two Idlib villages, Talmenes and Sarmin, in 2014 and 2015.

In October, a report from the commission concluded that the army carried out a chemical attack, probably with chlorine, at Qmenas in 2015.

On February 4, 2018, at least 11 cases of suffocation were reported at Saraqeb, the Observatory said, quoting inhabitants and medical sources who spoke of a “toxic gas”.

Idlib province is largely controlled by the extremists alliance Hayat Tahrir Al Sham (HTS), led by Syria’s former Al Qaida affiliate. Major Islamist rebel groups are also present in the area.

On February 18, 2018, hardline rebel Islamist groups Ahrar Al Sham and Nour Al Deen Al Zinki, present at the border of the provinces of Aleppo and Idlib, announced they were merging as the Syrian Liberation Front to counter the growing power of HTS in northern Syria.

The two coalitions engaged in deadly clashes in late February.

Idlib province is in theory one of the four “de-escalation” zones agreed by Turkey and regime supporters Iran and Russia in a bid to reduce violence.

However, since November pro-regime forces have been advancing from the neighbouring provinces of Hama and Aleppo.

In December, regime forces, backed by Russian airpower, launched an offensive to retake the southeast of the governorate.

Several weeks of deadly fighting allowed the regime to take control of some 400 villages and towns, as well as the military airport of Abu Duhur on the edge of the province.

The intensified offensive in Idlib coincides with a deadly regime push to retake the rebel enclave of Eastern Ghouta near Damascus.

On Friday, more rebel fighters evacuated one of the enclave’s three remaining pockets and a deal was reached for a pullout of militants and their families to Idlib from another.