Russia has announced a unilateral ceasefire in northwestern Syria, where Moscow-backed government forces have been waging a fierce offensive to capture the rebels' last major stronghold, from Saturday morning.
The announcement came on Friday as displaced Syrian civilians tried to push through a border crossing to enter neighbouring Turkey, amid an increasingly deteriorating situation in Idlib province
The United Nations has warned that the military push risks further fallout for the three million residents of the province, half of whom are already internally displaced from areas previously captured by forces loyal to President Bashar al-Assad. More than half a million civilians have been uprooted since the offensive began in late April, according to the UN, with over 500 people killed.
Russia, which intervened in Syria's long-running conflict four years ago to back al-Assad, said on Friday that an agreement had been reached on "a unilateral ceasefire by Syrian government forces in the Idlib de-escalation zone, from 6am on August 31".
The ceasefire aimed "to stabilise the situation" in Idlib, the statement said, urging anti-government fighters to "abandon armed provocations and join the peace process", the Russian Reconciliation Centre for Syria said in a statement.
There was no immediate response from rebel groups.
On Friday, Syrian troops captured several hills and small villages southeast of Idlib as they appeared to be trying to take as much ground as possible before the ceasefire went into effect.
In the renewed offensive, Russia and its Syrian ally have stepped up aerial raids on northwestern Syria, sending reinforcements from elite army units and Iran-backed armed groups, according to opposition sources, army defectors and residents.
The Russian-led alliance has taken the towns of Khwain, Zarzoor and Tamanah farms in southern Idlib, pushing closer into densely populated parts of the province.
The advancements were the first major gains since the alliance seized the main rebel pocket in Hama province last week.
Protests at the border
The fighting has sent hundreds of thousands of Syrians fleeing towards the border with Turkey. Thousands of them gathered at posts along the frontier, demanding Ankara's help to stop the deadly advance.
Protesters at at least one border post briefly forced their way into Turkey, but it was not immediately clear if they remained in the country or were pushed back into Syria, Al Jazeera's Bernard Smith, reporting from the Turkish border town of Bukulmez, said.
"What we saw earlier today was ... a seemingly concerted effort to rush those borders," Smith said. "And thousands of people in total tried it."
At the Bab al-Hawa crossing, Turkish border guards fired warning shots and tear gas to disperse the hundreds of protesters that had gathered, according to AFP news agency.
Mohammed al-Amouri, 53, said he attended the protest to demand Turkey keep its promises to prevent a full-scale assault on the Idlib region.
In 2018, Turkey and Russia agreed to establish a demilitarised "buffer zone" in Idlib between rebel and Syrian government forces to prevent an all-out assault, but the agreement has never fully been implemented.
A subsequent ceasefire agreed to by rebel groups and the Syrian government broke down on August 5.
Amid the escalation, Turkish President Recep Tayyip Erdogan on Tuesday met Russian President Vladimir Putin in Moscow. Afterwards, Putin told reporters the two sides had decided on "joint steps" to "normalise" the situation, but neither Ankara nor Moscow released any details.
"This is a warning to Turkey that we are coming to Turkey and to Europe if it doesn't do anything," al-Amouri told AFP. "These civilians can't take it any more," he said.
Turkey, which already hosts the most Syrian refugees in the world at 3.6 million, fears a full-force offensive by Syrian troops will send tens of thousands more refugees across the border.
Large portions of the Syrian countryside have already effectively been cleared of civilians, with satellite images showing towns and villages in Idlib "razed to the ground" in the fighting, Mark Lowcock, the UN emergency relief coordinator, said on Thursday.
"Over the last three weeks, since the collapse of the conditional ceasefire on August 5, dozens of communities have emptied out in northern Hama and southern Idlib," he said.
Turkey opened its borders to Syrians in April 2011, a month after the war began. But in recent years, Turkey has taken measures to slow the flow of refugees.
Rights groups have decried recent reports of hundreds of refugees being deported back to Syria as part of a crackdown on those without the right residency papers.
Turkey's government has flatly denied the reports, saying anyone returning to Syria - nearly 350,000 since the war began - has done so voluntarily.
"They are coming towards us and we need to be vigilant, we need to be cautious, and we have taken all the necessary precautions," said Erdogan, speaking after Friday prayers in Turkey's capital, Ankara.
"It would be a lie if we said the developments in Idlib are at the point we want," he said, adding the military was prepared with tanks and artillery and Turkey's 12 observation posts in Idlib were ready at all times.
Turkey's Foreign Minister Mevlut Cavusoglu said Russia has guaranteed Turkish observation posts in Idlib would not be attacked in advance.
Meanwhile, Syrian opposition sources said hundreds of troops from the country's elite Republican Guards, led by the president's brother Maher al-Assad in the capital, Damascus, as well as fighters from Lebanon's Iranian-backed Hezbollah group, have been deployed on the front lines of southern Idlib province.
"There are daily reinforcements coming from the Iranian militias, elite Republican Guards units and Fourth Armed Division," Colonel Mustafa Bakour, a commander in the Jaish al-Izza rebel group, told Reuters news agency.
The new lineup of forces has been credited with the rapid progress achieved in the last few weeks, an army defector and two senior opposition sources told Reuters.
"The Russians have now moved to depending on the Iranians and elite army formations in this campaign," Bakour added, saying this was a shift away from reliance on the so-called Tiger Forces who previously provided most of the Syrian army's ground troops.
Backed by a relentless aerial campaign, the recent offensive is seen as a breakthrough for Syrian government forces and their allies after months of costly battles.
Physicians for Human Rights (PHR), a US-based advocacy group which has documented damage to medical infrastructure throughout the Syrian war, has said that since the Syrian government and Russia launched an offensive on rebel-held areas in Idlib and northern Hama provinces on April 29, there had been credible reports of attacks on 46 healthcare facilities, of which it had fully verified 16.
It also said that from March 2011 through July 2019, 578 attacks have been carried out on 350 separate health facilities, over 90 percent by the "Syrian government and/or the Russian government".
The Russian and the Syrian governments have denied targeting civilian infrastructure. Syria's ambassador to the UN, Bashar Ja'afari, in July wrote a letter to the UN that all healthcare facilities in northwest Syria had been taken over by "terrorist groups" and were not performing humanitarian services.
Since capturing the strategic town of Khan Sheikhoun nearly 10 days ago, Russian and Syrian jets have been escalating raids on the city of Maraat al-Numan that lies further north.
At least 12 civilians, including five children, were killed during raids overnight on the now ghost city that has seen most of its over 140,000 residents flee in the last few weeks.