Syrian regime vows to 'go all the way' in Idlib attack

Syria's foreign minister said on Thursday that regime forces will "go all the way" in the rebel-held northern region of Idlib.

Idlib, which borders Turkey, is home to nearly three million people, up to half of whom are rebels and civilians transferred en masse from other territory that has fallen to Syrian troops after intense assaults.

Regime forces have been massing around Idlib for days and looked poised to launch what could be the last major battle of the civil war that has torn Syria apart since 2011.

Minister Walid al-Moualem said that Damascus' main targets were al-Nusra militants, adding that it would try to avoid civilian deaths.

Regime forces would not use chemical weapons in any offensive and do not have such weapons, he added.

The prospect of a massive Russian-backed offensive in a province that is home to some three million people - half of them already displaced from other parts of Syria - has raised fears of a new humanitarian tragedy.

The prospect of a massive Russian-backed offensive in a province that is home to some three million people - half of them already displaced from other parts of Syria - has raised fears of a new humanitarian tragedy

UN chief Antonio Guterres said on Wednesday he was "deeply concerned about the growing risks of a humanitarian catastrophe in the event of a full-scale military operation in Idlib."

One of the fears is that the regime will resort to using chemical weapons, as it did during an offensive against rebels in the Eastern Ghouta enclave earlier this year.

Another is the presence in the province of large numbers of fighters and civilians who have preferred to leave their homes rather than submit to Damascus rule.

Idlib has been used as a relief valve for those evacuated from other rebel pockets like Eastern Ghouta following their negotiated surrender to the regime.

But fighters who reject similar surrender deals for Idlib will have nowhere to go, heightening the chances of even deadlier battles if an all-out offensive is launched.

Humanitarian corridor

The UN's Syria peace envoy offered on Thursday to travel to Idlib to help ensure civilians can leave through a humanitarian corridor amid fears of an imminent regime offensive.

"I am once again prepared... personally and physically to get involved myself... to ensure such a temporary corridor would be feasible and guaranteed for the people so that they can then return to their own places once this is over," Staffan de Mistura told reporters in Geneva.

A major military operation in Idlib would pose a particular humanitarian nightmare because there is no nearby opposition territory left in Syria where people could be evacuated to.

"There is no other Idlib," de Mistura said, stressing the need to ensure civilians can evacuate to nearby areas under government control, with guarantees their rights will be respected once they get there.

"It would be a tragic irony frankly if at almost the end of... a territorial war inside Syria, we would be witnessing the most horrific tragedy to the largest number of civilians," he said.

De Mistura stressed the need for "constructive, effective" support from Damascus, since the possible corridor would most likely need to lead into regime-controlled territory.

"Short of going to Turkey, the civilians have no other option in order not to be where fighting may take place."

The most important thing, he said, was to avoid "a hurried escalation", which could easily lead to "the worst-case scenario."

"It would be quite tragic at this stage, having seen how difficult the seven years (of Syria's war) have been."

Turkey, Russia and fellow regime backer Iran all operate "observation points" in Idlib as part of a "de-escalation" deal agreed last year that was meant to reduce bloodshed in the province.

But with a regime offensive looming, the Turkish military has been reinforcing its 12 monitoring posts.

During a press conference with his Saudi counterpart in Moscow on Wednesday, Russian Foreign Minister Sergei Lavrov hinted the assault may be imminent.

"It is necessary to disassociate the so-called moderate opposition from terrorists and at the same time prepare an operation against them while minimising risks for the civilian population," Lavrov said. 

"This abscess needs to be liquidated."