When the spicy lamb haneeth arrives at the table of New York’s Yemen Cafe, the world’s worst humanitarian disaster can seem very far away.

But as the men at the table tear into sheets of charred bread straight from a clay oven, lunchtime conversation on Brooklyn’s busy Atlantic Avenue is dominated by news of atrocities happening back east.

It’s half a world away geographically, but so close spiritually, and loved ones trapped in the conflict are on everyone’s mind. “They are suffering right now,” American-born Sam Quhshi says. “We are their life support; if they lose us they have nobody.”

The latest heartbreak involved the shocking news that American-made weapons were used in an airstrike that killed dozens of children on a school bus as they were coming back from a picnic.

This week UN investigators reported that all parties in Yemen’s bloody conflict may have committed “war crimes”, adding that Saudi-led coalition airstrikes had caused “most of the documented civilian casualties”.

This cafe has been here since the 1980s and has always functioned as a meeting place and a home away from home for Yemenis. The men around the table are a mix of American-born and more recently arrived, all part of the diaspora that started making New York home in the late 19th century, but really picked up the pace in the 1950s.

Yemenis run more than 1,000 of New York’s local food stores, known as bodegas, and Brooklyn is home to one of the largest communities of the estimated 400,000 Yemenis in the US.

Left to right, Sam Quhshi, Ghamdan Shahbain, Husam Kaid and Younis Ali at the Yemen Cafe, where recent conversation has been dominated by the humanitarian crisis underway in Yemen. Photograph: David Taylor/The Guardian

Today Yemeni Americans, who have traditionally sent home money to help build up their country, are anguished by the war, which has killed 6,600 civilians since 2015 and brings almost constant news of fresh calamities.

Their pain is made worse by Donald Trump’s travel ban, which was inspired by fear of terrorism but has left innocent civilians trapped in a conflict zone, many of them relatives of American citizens.

Ghamdan Shahbain, 31, a father of two who runs his own businesses, said of the airstrike on the school bus: “It hurts, it is a tragedy, it’s a crime, it’s very devastating. They were just kids, trying to live their life.

“Before this war broke out we were struggling with the economy, the last thing we needed was a war.”

His cousin Younis Ali, 32, an American-born playwright, said news that American missiles were used in the strike was not a surprise. “The US has been backing Saudi Arabia ever since they started this fight. Saudi Arabia does not have the interests of Yemen at heart and Yemenis are aware of that.

“The fact that they hit a school bus, the majority of them under 12 years old coming back from a picnic – what kind of intelligence could merit a strike of that sort in the middle of a marketplace? There is very little concern for the civilian population.”

UN-mediated talks are set to begin on Thursday in Geneva, between Yemen’s government and the Iranian-backed Houthi militias, the first attempt in two years to start peace negotiations.

But western powers have done little to seek a solution to what has become a proxy war between Saudi Arabia and Iran. As the New York Times put it this week, there is “American complicity” in what the UN has called criminal carnage.

US support for the Saudi-led airstrikes started under Barack Obama, but he banned sales of precision-guided missiles after the 2016 bombing of a funeral in which 155 people died. Trump overturned the ban almost immediately after taking office.

Debbie Almontaser, one of the founders of the Yemeni American Merchants Association, organised a symbolic one-day strike of the bodega stores, shuttering 1,000 shops and bringing 6,000 politicised Yemenis onto the Brooklyn streets in protest of Trump’s travel ban.

“We knew from the start that the US has not played a good role,” she said in a telephone interview, urging America to get off the sidelines. “I would like to see my country take a higher road.”

Back at the Yemen Cafe, one of the group tells of a brother whose wife was stranded after her visa was torn out of her passport by airport officials as she tried to travel with her children to safety in the United States. Two of her sons who are American citizens had to leave her behind and travel to the US.

Sam Quhshi, 40, owns businesses and works on Wall Street in investor relations and has lost property and investments back in Yemen.

The Yemen Cafe in Brooklyn, New York, has become a ‘home away from home’ for many Yemeni Americans. Photograph: David Taylor/The Guardian

The youngest, 19-year-old Husam Kaid, a student, talks about fundraising for a New York charity that helps feed hundreds of families in Yemen every day.

All of them want to see America step up and help end the conflict.

Quhshi said the Houthis had gone from a little understood fringe group to gaining support. “The Saudis lost the hearts of the Yemenis from day one when they started targeting civilians,” he said.

“I’m not here to take sides, but after the last three or four years, if I have to choose sides, I would choose with my own people, because the Houthis are still from Yemen. They are the only guys in town who are actually fighting for Yemen.”

By the time the cardamom tea arrives, Ali talks about taking part in the New York Rep’s Imagine: Yemen, a series of new short plays. He tends toward writing comedy, but took part in the event, which told stories of children trapped in the conflict.

“We are trying to get that message out about what is happening to the children. It’s ironic that as that’s going on you have something like the travel ban,” Ali said. “America is supporting the Saudis killing people in Yemen and doing the travel ban at the same time to stop people getting out.

“An entire generation of Yemenis are being wiped out. If they wanted to stop it they could.”