MONTREAL — The crowd of asylum seekers who gathered the other day outside this city’s Olympic Stadium, their temporary home, hailed from across the globe. They had fled violence, poverty, persecution and, some say, President Trump, often with only a suitcase to their name and a wisp of hope that Canada will allow them to stay.

They are part of a new surge of mostly Haitian migrants who have illegally crossed into Quebec by the hundreds every day over the past several weeks, walking over a ditch at the end of a dead-end road in upstate New York. They are seeking to benefit from a loophole in a treaty between the two countries that allows them to make refugee claims in Canada if they do not arrive at legal ports of entry.

“I lost everything in Haiti, but now I’m afraid the U.S. will send me back,” said Jonathan Luima, 44, a Haitian migrant who arrived in the United States last year. “Canada is my only hope.”