Traffic is heavy on the roads heading north through the Idlib region toward the Turkish border. Soldiers of the Assad regime are advancing from the south and east, aided by their Russian and Iranian allies. Some Syrian rebel groups are supported by Turkey, which also has soldiers of its own in the region. But ordinary people just want to reach safety.

Almost 1 million people have been displaced since December. According to UN humanitarian chief Mark Lowcock, "the horror has multiplied" in the past two weeks. The front lines are closing in, triggering large movements of people in the space of just a few days. Assad wants to drive the civilian population out of Idlib province, and is moving to capture this last rebel stronghold.

Maaret al-Numan and the surrounding area has been particularly badly hit by the attacks. The city has been bombed to pieces and is practically deserted. The important M5 highway runs through here, from Damascus via Aleppo to the Turkish border. Most of those fleeing are trying to make it to Turkey — but the border is closed.

Around 100 people, including 35 children, died in bombings in the first half of February alone, according to the United Nations, which has spoken of the "blatant disregard for the life and safety of civilians." This family fled to the Turkish border months ago. They're living in the Kafr Lusin refugee camp, holding on to the hope that Turkey will eventually let them in.

Out of the almost 1 million people who have fled it's estimated that around half are children. Of the rest, the majority are women. There aren't enough shacks at the Turkish border to house them all, and many refugees are living in tents. Camps are often set up in haste and are severely overcrowded. People are sleeping in doorways and on pieces of cardboard, sometimes in sub-zero temperatures.

Those who have been able to find a tent usually share it with about a dozen family members. Medicine is running out in many of the camps, and basic food and clothing is also becoming scarce. Doctors on the ground report that many children are suffering from malnutrition, and some are even dying of starvation. The cold is also taking its toll, and some people have already frozen to death.

Many children in the region can no longer go to school, so some school buildings have been repurposed. This school has been turned into a refugee shelter — sometimes, even the refugee camps are targeted in bombing raids.

The illegal route across the border to Turkey is costly; hardly anyone can afford it. Smugglers are charging people up to $2,000 (about €1,800). Those who do make the attempt are risking their lives: Turkish border guards have thermal imaging cameras to help them spot people trying to cross. Sometimes they shoot at refugees who try to climb over the wall.

The UN has said the situation in Idlib could be the greatest humanitarian disaster of the 21st century. No one knows whether or not there will be a ceasefire. The refugees don't care who puts an end to the war; they just want a life of safety and dignity, for themselves and for their children. A four-way summit between Turkey, Russia, France and Germany, planned for March 5, is now in jeopardy.

Syrian troops have intensified their push for the country's last major rebel enclave — a "prelude to their total defeat," according to President Bashar Assad. The violence and mass displacement could result in the biggest humanitarian horror story of the 21st century, said the UN's humanitarian and emergency relief head, Mark Lowcock. Children in particular have become the face of this suffering.

Of the almost 900,000 forced from their homes and shelters in the last three months, 80% have been women and children, a UN spokesperson said. Around 300,000 of those have fled since the start of February alone. The wave of displacement is the largest exodus of civilians since World War II.

With temperatures reaching minus seven Celsius (19 degrees Fahrenheit) at the snow covered displacement camps in the hills near Turkey's borders, seven children have died from exposure and bad living conditions. Save the Children said families are burning whatever they can find to stay warm. The chairty warned the death toll could rise.

Convoys of Turkish commandos rolled toward the former "de-escalation zone" as Russian-backed Syrian forces intensified their push to retake the area in late January. After 13 Turkish soldiers stationed there to support rebels were killed in early February, diplomatic efforts to broker a cease-fire stalled.

Assad's offensive to retake the strategic M5 highway leading through Idlib province to Syria's second city, Aleppo; has been a long-term objective. After a Russian bombing campaign helped Syrian forces capture all towns along the route on February 11, fierce fighting in western Aleppo forced more than 43,000 toward the Turkish border.

The sheer number of Russian and Syrian aerial and artillery attacks on displacement camps, hospitals and schools "suggest they cannot all be accidental," UN human rights spokesperson Rupert Colville said. His office has recorded 299 civilian deaths this year, 93% caused by the Syrian government and its allies. Michelle Bachelet, the UN's human rights chief, called the campaign "indiscriminate."

Turkish-supported rebels have been caught out by the onslaught, as have jihadis who are not officially backed by Ankara. One Islamist group, Hayat Tahrir al-Sham, scored a rare victory last week when they downed a particular model of helicopter that Syrian forces are thought to use to drop barrel bombs on civilians.

The UN's Bachelet said "no shelter is now safe" and displacement camps have been overwhelmed by the number of those fleeing from the violence. Many have left the camps to take their chances on the road. Bachelet called for humanitarian corridors to be established to allow civilians to escape.

Turkey has closed its borders to prevent a further influx of Syrians. It already hosts 3.5 million refugees. That leaves the people of Idlib with no escape route. More than 500,000 of those fleeing are children.