Hodeidah, the densely populated Houthi-held Yemeni port city, is bracing for the worst as it faces an all-out battle, humanitarian groups said Friday.
A Saudi-led coalition is working to take the city back from the Houthis, its foe in Yemen's bloody civil war. The fighting is taking place on the outskirts of Hodeidah, with clashes involving heavy artillery south of the city, according to Houthi sources.
The last CARE staffer remaining in the city said the mood is dire.
"Jets have been hovering over the city since 4 a.m. in the morning. The situation is very scary, scarier than it has ever been before. We can hear the fighting coming close, and the situation is really changing for the worse," the staffer said.
Hodeidah is on the Red Sea in western Yemen. Though the city's port still seems to be open, CARE said it can't confirm that goods are able to move into the country.
The International Committee of the Red Cross said on Twitter that Yemenis "fear a siege" and "are under "immense pressure," with people scrambling for food and safe shelter.
"You can feel the tension in the streets. Instead of focusing on celebrating #Eid with their families, people are stocking up on food and fuel to survive," the ICRC said, referring to the Muslim celebration marking the end of Ramadan.
Outside the ICRC office is a dirt patch, "where children play football casually under the sound of gunfire and airstrikes."
The ICRC team said the signs of poverty are widespread, with people in slums "surviving on bread crumbs they find in the garbage."
"Beggars are everywhere," it said.
Hospitals are hampered by a lack of electricity, and generators do not have enough fuel. Tens of thousands are likely to flee Hodeidah in the coming days, the ICRC said.
Yemen's war began in early 2015 when Houthi rebels -- a minority Shia group from the north of the country -- drove out the US-backed government, led by President Abdu Rabbu Mansour Hadi, and took over the capital, Sanaa.
The crisis quickly escalated into a multisided war, with al Qaeda and ISIS growing stronger amid the chaos.
The Houthis are backed by Iran, and its members follow the Shia Islamic branch of Zaidism. Zaidis, who make up around a third of Yemen's population, ruled the country's north for almost 1,000 years until 1962.
The Saudi-led coalition began its air raids in support of Hadi's government in March 2015.
"About 70 percent of Yemen's aid and commercial imports enter through Hodeida and the nearby Saleef port, providing food, fuel, and medicine that the population needs for survival," Human Rights Watch said. About 600,000 civilians remain in the region, the group said.
Sarah Leah Whitson, Middle East director at Human Rights Watch, said both the coalition and the Houthis have "atrocious" records adhering "to the laws of war."
"The UN Security Council should urgently warn senior officials on both sides they will face sanctions if they fail to provide civilians access to desperately needed aid," Whitson said.
"The battle for Hodeida could have a devastating impact on civilians both in the city and elsewhere in Yemen. Both sides need to seek to minimize civilian harm at all times, whether in carrying out attacks or by allowing families to flee to safety."
The war has become the world's worst humanitarian crisis, with more than 22 million people -- three-quarters of the population -- in desperate need of aid and protection, UN Secretary-General Antonio Guterres said in April.
As the conflict enters its fourth year, millions are without access to clean drinking water, and the country is at high risk of a cholera epidemic, Guterres said.
With Western media focus on Syria, Yemen's conflict is often called the "forgotten war." The situation there is now catastrophic, with "nearly half of all children aged between 6 months and 5 years old chronically malnourished," according to Guterres.
The battle for Hodeidah "could have a devastating impact on civilians both in the city and elsewhere in Yemen," Human Rights Watch's Whitson said.
"Both sides need to seek to minimize civilian harm at all times, whether in carrying out attacks or by allowing families to flee to safety."