For Most Refugees in Canada, a Warm Embrace. For Others, Jail.

His attempt to escape deportation from Germany by hiding on a westbound freighter — under the cargo cover of a new BMW — was desperate and ill conceived. With only 1.5 liters of water and some nuts and dates, Walid Kabil did not have enough supplies, heat or space to survive the April voyage.

He feared being returned to Morocco, where he said he had been arrested because of his political activism. But cold, aching and dehydrated, he sought help from the ship’s crew.

Then came the surprise. After the ship docked in Halifax, Nova Scotia, and he was handed over to Canadian border authorities to make his asylum claim, Mr. Kabil was sent to a provincial jail filled with people accused of violent crimes, including murder.

Prime Minister Justin Trudeau has told asylum seekers on social media that his country welcomes “those fleeing persecution, terror & war,” but Mr. Kabil and thousands of others seeking asylum have found that the welcome does not always apply to them.

Government officials say only a small percentage of asylum seekers are detained because they could be a risk to public safety or disappear into the country. One expert on immigration said it was an important tool to control undocumented migration.

Like the United States and other Western countries, Canada is increasingly struggling to accommodate asylum seekers who some critics say are adding to a strain on government services.

The questions being raised about asylum seekers who arrive without a sponsor or documentation focus on how often and for how long they should be detained while they wait for their claims to be heard and what detention says about the country’s self-image as a nation open to migrants.

In the United States, where immigration is a central issue in the November election, President Biden has moved to temporarily block most asylum seekers at the southern border after the number of migrants crossing illegally reached historical highs.

In Canada, Carl Desmarais, a top official at the Border Services Agency, which inspects all people and cargo entering the country, called detention “a measure of last resort.”

But human rights groups and other detractors say it should be used even more sparingly because most asylum seekers are not a threat to commit crimes or abscond.

“The default position should be that people are released into the community pending the determination of their legal status,” said Alan Rock, a former national justice minister who has been pushing to end detention.

Last year 29,455 refugees sought asylum from border guards when they arrived in Canada. During the most recent fiscal year, which ended on March 31, 5,800 asylum seekers were held in provincial jails or immigration detention centers.

Those detained were held an average of 16.5 days, while 7 percent were held for more than 99 days.

While polls show that Canadians broadly support immigration and admitting refugees, that support has softened somewhat, particularly because some economists say immigration-driven population increases are contributing to rising housing prices.

François Legault, the premier of Quebec, in an open letter to Mr. Trudeau in January, pleaded with the federal government to reduce the influx of refugees into his province. “We are close to the breaking point because of the excessive number of asylum seekers,” he wrote. “The situation has become unbearable.”

Mr. Kabil, the Moroccan migrant, said he was shocked when he learned that he was being detained.

“When I came here it was like: O Canada, the dream, I’m going to be safe,” he said. “But then suddenly it was, ‘You know that you’re going to be in jail.’”

He was released after 11 days and was granted refugee status in late 2021, four and a half years after he arrived in Canada.

The Canada Border Services Agency declined to comment on Mr. Kabil’s case because of privacy laws.

Migrants who are locked up tend to be asylum seekers who enter the country by other means — usually by air traveling on a tourist or student visa and occasionally as stowaways on ships. (Under agreements with Washington, migrants who walk into Canada across its border with the United States are quickly returned south.)

Some detained migrants are awaiting deportation after their asylum claims were turned down. But an analysis by Human Rights Watch and Amnesty International found that most were waiting for their claims to be heard, a process that can drag on for years.

One man believed to be from South Africa was held in an Ontario jail for 11 years because his identity could not be determined.

Since 2000, at least 17 detainees have died in immigration custody, according to research by Human Rights Watch.

Because the border services agency is not required to announce the deaths of people in immigration custody, an exact count could not be determined, said Samer Muscati, who investigates immigration detention for the group.

Last year, a coroner’s jury in Ontario looking into the 2015 death in immigration detention of a 39-year-old Somali man with mental illness recommended the creation of an oversight body to investigate the conditions of people while in immigration custody. But there has been no movement on the recommendation.

When asylum seekers are detained, the border services agency is required to bring them before the Immigration and Refugee Board of Canada within 48 hours. But advocates say the process is flawed and inconsistent.

In some cases, the agency will argue that “this person’s a flight risk because they have close ties to their community in Canada,” said Julie Chamagne, the executive director of the Halifax Refugee Clinic. “Then they show up at the next hearing and say the person is a flight risk because they don’t have close ties. It’s very, very, very frustrating.”

Canada does not track how many asylum seekers commit crimes unrelated to immigration. But less than 2 percent of people in the last fiscal year failed to appear for immigration hearings, according to the Immigration and Refugee Board.

While detention is a serious measure, it is crucial to Canada’s border security strategy amid a global refugee crisis, said Christian Leuprecht, a political science professor at the Royal Military College of Canada in Kingston, Ontario.

Detention, he added, helps safeguard “Canadian sovereignty, Canadian rule of law and the prosperity, stability and social harmony which makes this country so attractive for people to come here to begin with.”

Human Rights Watch, Amnesty International and others have lobbied Mr. Trudeau’s government to push the border agency to reduce detentions. But the agency largely operates independently from the government and has no independent civilian oversight body.

Following lobbying by human rights groups, Canada’s 10 provinces have said this year that they will not renew contracts allowing the federal government to use their jails for immigration detention.

The border services agency said it was filling the void by expanding the three detention centers it now operates.

The agency, as part of the federal budget being considered in Parliament, could also receive funds to build new segregated immigration detention facilities within federal prisons. Border officials said asylum seekers would generally be separated from the criminal population.

Hediyeh, a 28-year-old Iranian woman who asked to be identified by only her first name to protect relatives back home, fled to Canada because of what she described as violent behavior by her father, a government official and religious figure, who opposed a romantic relationship.

Her father, she said, beat her with a belt and wrapped a plastic bag over her head until she passed out. Relying on smugglers and a forged Danish passport, she took a series of flights before finally arriving in Halifax.

At first, Hediyeh said she was not worried.

“In my country, we just know that Canada is a perfect country,” she said. “You always hear a lot of good things about it, that it’s safe, especially for women, that it is going to help you. So I arrived and I was happy. I was, ready to explain everything.”

After a hearing in English, which she did not understand at the time, Hediyeh thought she was going to a hotel. Instead, she was sent to a Nova Scotia provincial jail.

She said she spent two days in solitary confinement.

Then she was transferred into the general prison population, where violence was common. She carried her clothing into a shower after seeing someone steal another prisoner’s garments.

“It was so scary; lots of things were going on,” she said. “I realized, ‘My god, I’m in the real, real jail.’”

Hediyeh was released after one month, and her claim to stay in Canada was eventually accepted.

Vjosa Isai contributed reporting from Toronto; Hamed Aleaziz from Healdsburg, Calif.; and Miriam Jordan from Los Angeles.