With thousands of migrants stuck at the Greek-Macedonia border and 2,000 arriving daily, authorities warn that the stranded migrants could surge to 70,000 in a matter of days. (The Washington Post)

In a cold drizzle, Aziza Hussein, a 30-year-old Syrian widow traveling with her four children, stood amid a surge of migrants trapped at the northern Greek border. Her way forward blocked by armed Macedonian troops, police dogs and a razor-wire fence, she stood in the middle of the chaotic scrum of refugees, clutching her 5-year-old son.

“What are we going to do?” she said, shielding her eyes with a trembling hand as she cried.

In recent days, European nations have moved more aggressively than ever to shut down the route used by more than a million migrants fleeing war and poverty in the Middle East and beyond. Yet even as they do, the region is confronting a new kind of migrant flow — waves of women and children.

Last year, most of the asylum seekers fleeing to Europe were men, many of them young and single. But in the past several weeks, the balance has shifted, with women and their children, as well as unaccompanied minors, now accounting for roughly 57 percent of asylum seekers.

The surge of the vulnerable comes at the worst possible time — just as European nations are barring their doors and 25,000 refugees are suddenly trapped in near-bankrupt Greece, a country that was once merely an entry point.

An Iraqi mother with her daughters cries as a frantic crowd on the Greek side of the Greece-Macedonia border tries to break through the border fence on Feb. 29, 2016. (Jodi Hilton /For The Washington Post)

Refugees say the sudden exodus of women and children was sparked by a rising fear that the path to sanctuary will soon close completely.

“My cousins, my neighbors, everyone told us, ‘Go now. There isn’t much time, because they will shut the door,’ ” said Hussein, who left the Syrian city of Hasakah three weeks ago in a desperate bid to make it to Germany.

“We crossed the sea,” she said, pausing to wipe away tears. “But they won’t let us through. You don’t understand. I don’t have any money left. I have four children. I don’t have any other plan.”

Now, the European Union’s most troubled member — Greece — is scrambling to cope with a mounting humanitarian crisis the rest of the continent has left on its doorstep. With 2,000 migrants a day still arriving in rickety boats in the Greek islands via Turkey, Greek officials are warning that the number of stranded migrants could surge to 70,000 within 30 days, turning pockets of this troubled country into sprawling refugee camps.

In a tacit acknowledgment of the burden being put on Greece, E.U. officials on Monday were preparing a humanitarian aid package largely aimed at helping the government in Athens cope. But even as they did, the situation was already in danger of spiraling.

Here at the primary northern border crossing, at Idomeni, 7,000 migrants — with more arriving — were stranded Monday in a fetid camp and facing a deeply uncertain future. With more children in the camp, flu, lice, stomach bugs and other ailments were spreading more rapidly, aid workers and migrants said. There were only 30 showers for the camp. Some Muslim women, unwilling to walk back to their tents in wet clothes through crowds of men, are choosing not to bathe at all.

“I haven’t showered since Feb. 18,” said Hanan Alkhalii, 30.

In recent days, Macedonian authorities have begun sharply limiting the number and type of migrants allowed through — a response to the same action by Austria, Slovenia, Croatia, Serbia and other Balkan nations. Macedonian authorities on Monday resorted to tear gas, firing canisters at migrants as they tried to force their way through a section of border fence with a battering ram.

Hours later, children could still be seen rubbing at irritated eyes.

“We treated women and children today because of tear gas,” said Vicky Markolefa, a visibly frustrated official with Doctors Without Borders, which is running an overburdened clinic here. “Yes, that’s right. Women and children. They were choking. They had stinging eyes. They inhaled that smoke. Some of them were infants.”

As the bottleneck grows worse, the camp has reached four times its capacity. Aid groups have run out of tents and blankets, so hundreds of asylum seekers, including children, are sleeping outdoors in the rain in 54-degree weather.

On the road leading to the border crossing, women in headscarves holding the hands of small children could be seen making the 15-mile trek from the nearest bus stop. Once they get to the crossing, the line for food — on Monday, fried-potato sandwiches — was three hours long.

“We can’t take this,” said Shaza Hamdune, 31, a Syrian widow and elementary school teacher traveling with her two young children. They have been stranded here for 10 days, she said, spending the first three nights under open skies before some Syrian men gave them a tent. She said she left Syria 20 days ago after her brother, who made it to the Netherlands last year, warned her to come now or risk not coming at all, given the anti-migrant sentiment spreading across Europe.

“My son, when he saw the tear gas today, he clung to me because it reminded him of the war,” she said.

Last week, Macedonia — which in November had limited crossings to just Afghans, Syrians and Iraqis — stopped allowing in Afghans. As a result, Afghan nationals were being bused from the border back to Athens even as Greek authorities were racing to open five new migrant camps in the north for those unable to cross.

In the past, most Syrians and Iraqis were waved through if they could provide basic identification — something European officials now say may have helped extremist militants to slip into Europe disguised as migrants. In recent days, however, that has changed. Syrians and Iraqis now must provide passports, birth certificates or other evidence of their nationalities.

Even then, crossing the border is hit-or-miss. On Sunday, about 300 people made it. On Monday, only a handful were through by late evening.

Greek police say almost a third of the Syrians and Iraqis are now being turned back because of a lack of paperwork. That is exactly what worries Dareen Ghazal, 34.

She is a Syrian traveling with four children after her husband made it to Sweden last year. But their hopes to have him bring her and the children over legally have been frozen in bureaucracy and stiffening laws requiring migrants to wait longer before close family members can join them.

But, like so many others here, Ghazal does not have proper papers. She had a passport, she said. But the smuggler she paid to get to Greece threw the backpack with her passport into the sea when their boat started to sink.

“Now they say we cannot cross without a passport,” she said. “Where am I supposed to get another one? I cannot go back to Syria. I won’t. I can’t.”

Elinda Labropoulou contributed to this report.

Read more:

Could Europe’s refugee crisis be the undoing of Angela Merkel?

Today’s coverage from Post correspondents around the world