TIJUANA — The first wave of migrants — unthinkable until then in this border region — arrived unannounced last May after an interminable slog across the American continent.

Three hundred people — the majority from Haiti, a few from Africa — turned up in this Mexican city of 1.3 million inhabitants to try their luck getting into the U.S. as refugees. In the weeks following last May, other waves of Haitians and Africans appeared.

Fast forward to this year's rainy January. About 5,000 migrants of all ages are stuck in Tijuana. While the Obama administration used to let in about 50 migrants into the U.S. every day, U.S. President Donald Trump bars them from accessing the country of their dreams. Officials in Tijuana don't know what to do. Refugee centers are overwhelmed. A humanitarian crisis looms. And yet, each day, scores of migrants continue to arrive.

Near the steel wall that separates Mexico and California at the corner of Melchor-Ocampo avenue, which has become potholed after incessant rain and neglect from local authorities, groups of Haitians chat while policemen look on. "We weren't expecting them," one of the officers says.

Across the street, sheltered under a sort of archway, dozens of homeless Mexicans lie amid a mess of soiled blankets and pillows.

"As if Tijuana didn't have enough problems as it is," one Mexican man mumbles. The migrants have hacked the city's electric cables to charge their phones but the security forces don't seem to care. The mood is calm but the setting is bizarre.

The migrants are gathered at this crossing because of its proximity to Desayunador Salesiano Padre Chava, a refugee shelter.

"Before their arrival, we mostly gave breakfast to those evicted by the Obama administration, to migrants from Central America and to recovering drug addicts," says Claudia, a social worker. "We have an 80-bed capacity. We are currently sheltering 391 people."

At nightfall, the gigantic "dining room" of the Desayunador turns into a dormitory. Since it's not large enough, the patio outside was turned into a makeshift camp. Tents are a mix of tarpaulins, blankets and plastic bags.

"I've been here for weeks and I'm fed up," says Josué, a 30-year-old Haitian artist. "The Mexicans don't respect us. As refugees, we have the right to housing, work and food." He uses an expletive to describe the infrastructure in Mexico.

His remarks aren't really fair. The inhabitants of Tijuana are doing what they can with their meager means since the federal government doesn't offer much aid. A total 300 million pesos ($15 million) is allocated annually to states hit by the migrant crisis, including 7.7 million to Baja California. Even with a shoestring budget, Desayunador manages to feed migrants three times a day.

"It sounds incredible but they're never happy," says Claudia. "They don't like Mexican food and they complain about it. They have no notion of order, limits and rules. It's not easy for us."

After breakfast, migrants have to leave so volunteers can clean the shelter.

"They dispute this rule," a Canadian missionary says. "And they refuse to give us a hand. We are astonished by their demands. It's not as if they've come to a rich country."

At refugee center Juventud 2000 a few kilometers away, it's the same story. The center has a capacity to hold 70 people but shelters 185 migrants. The center's courtyard is hidden under a pile of tents and laundry.

Doathy, a 27-year-old Haitian, is resting. Her lover Moussa, a Ghanaian she met during the journey here, is caressing her ankles. Doathy is three months pregnant.

"Mexicans are racist," she says. "Believe me when I say that we are invaded by stink bugs, that we get served the same food every day, and only once a day, that the center's manager doesn't even let us charge our cell phones. They don't give a damn about us."

Questioned on that point, the concerned party, José Maria Garcia, shakes his head, incredulous about his guests' ingratitude.

"My budget is minimal. And I'm lucky enough that my father owns this building and doesn't ask me to pay any rent. I only get 250,000 pesos ($12,000) a year from the federal government," he says.

He shows us his last electricity bill — 9,637 pesos for two months.

"I can't afford a higher bill. Same for meals. I wasn't prepared for the arrival of these migrants. Nobody was in Tijuana. They didn't warn us they were coming. Haitians are complaining even though Mexico grants them a special status. When they enter the country via the Chiapas state, the government grants them a 20-day permit to cross the country. So they're not harassed like other migrants, like those from Central America, for instance," he says.

"What will they do when the U.S. shuts the door in their faces? Because that's what will happen with Donald Trump."