Saudi Arabia is discussing plans to deploy ground troops with regional allies, including Turkey, for a safe zone in Syria, in a last-ditch effort to keep alive a rebellion at risk of collapse as a Russian-backed offensive by Syrian regime forces encroaches on the northern province of Aleppo.

Although western officials have dismissed the plans as lacking credibility, they are a sign of the desperation that many of Syria’s opposition backers feel towards what looks like an increasingly bleak outcome to the war.

Two people familiar with Saudi plans told the Financial Times that high-ranking Gulf officials are in Riyadh meeting Turkish officials to discuss options for deploying ground troops to head a coalition of fighters inside Syria.

Aleppo city, Syria’s former business hub, is the last major urban centre controlled by the rebels.

Its countryside, on the northern border with Turkey, is their lifeline.

President Bashar al-Assad’s forces, bolstered by Iranian-funded Shia militias, advanced last week into opposition-held territory in Aleppo’s northern countryside under the cover of Russian air strikes.

The violence prompted thousands of civilians to flee, exacerbating the already vast humanitarian crisis.

Publicly, Saudi Arabia, the UAE and Bahrain are calling for troops to be deployed as part of the US-led international coalition already ranged against Islamic State.

This comes after Washington singled out Arab countries for not doing more to fight Islamic State, also known as Isis.

But regional observers say that the moves are cover for an intervention to help the Syrian rebels.

International ground force

“We’re not there yet, but we are very close,” one person familiar with the plans told the Financial Times, asking not to be identified.

The plans appear to be led by Riyadh’s defence minister and deputy crown prince, Mohammed bin Salman, whose involvement makes some diplomats reluctant to rule out an attempted intervention.

“I see all kinds of red flags. But there is a new level of unpredictability and erratic behaviour in the new Saudi government,” said one western diplomat.

“With Mohammed bin Salman, you just don’t know.”

A Saudi official said “there is not a single plan yet [on military action], the coalition is yet to decide.”

Turkey, frustrated with US support for a Syrian Kurdish militia, the YPG, has its own reasons for intervening.

It is keen to undo advances made by the Kurds along its border, said one Turkish official.

However, a senior official in the Turkish prime minister’s office denies that it is preparing to send ground forces.

“All these reports regarding this huge number of troops are baseless – Yes, we are talking to the Saudis and to all partners on how to support the moderate opposition.

“As a coalition partner to fight Daesh [Isis], Turkey has a close dialogue and co-operation with a large number of countries.”

Dramatic escalation

And any action risks causing a dramatic escalation in the multi-sided Syrian war, which has killed around 300,000 people, incubated jihadi militants and driven hundreds of thousands of refugees to Europe.

If Saudi and Turkish forces were deployed at Syria’s northwestern border crossings with Turkey, for example, they would be inside Russia’s operational theatre.

They would also be adjacent to territory controlled by the YPG, which is both a US ally against Islamic State and a PKK affiliate.

“This would be a total nightmare for the US,” said analyst Aaron Stein, of the Atlantic Council in Washington.

“What happens if Russia kills a Turk? They would be killing a Nato member.”

Those familiar with the Saudi plans say back-channel conversations are being held between Saudi and Russian officials over outlining theatres of operations - one for the Gulf and Turkish-backed rebels, and a region for Mr Assad and his backers.

If true, the most likely option would be to try to set up a base for rebels in eastern Syria, which is currently held by Islamic State.

That would likely entail a long and bloody battle, and many rebels may be unwilling to give up fighting the regime for Aleppo and northwest Syria.

Safe zone

Russia is already backing a second regime offensive in the area, and Jordan may be more interested in reaching a deal with Moscow.

Turkey has one means of exerting pressure on western countries: the tens of thousands of Syrians who fled the offensive and are being held back at its borders.

It may try to demand a safe zone for them inside Syria or else threaten to allow them to flow unhindered toward Europe.

In the absence of a safe zone, the most likely scenario is that Turkey and the Gulf countries simply increase the supply of higher quality weapons to rebel fighters.

That option worries some Syrian rebel leaders, who say Moscow would simply respond with more powerful arms.

“We are heading for major escalation,” a commander in the Syrian opposition’s Southern Front said.

“I have lost all hope for the revolution. But the war is far from over.”

Copyright The Financial Times Limited 2016