US closes major crossing as caravan migrants amass at border in Mexico

A Honduran migrant lies on the riverbank as Mexican police move away from tear gas fired by US agents at the Mexico-US border in Tijuana, Mexico. Photos / AP

United States authorities closed off the busiest port of entry along the border with Mexico and fired tear gas at members of a Central American migrant caravan who had rushed the fencing that separates the countries.

Although the number of of people in the caravan was relatively small, the unrest, with migrants attempting to climb fences and run through car lanes to reach the US, and scenes of mothers and children choking on tear gas, represented a serious escalation of the caravan crisis.

What had begun as a migrant protest of the slow pace of the US asylum-claims process devolved into a chaotic scramble in which hundreds made their way to the border, hoping to cross onto US soil.

To block that from happening, and as some threw rocks and bottles, US authorities took the rare step of firing tear gas into Mexico as well as closing all legal vehicle and foot traffic to the San Ysidro border crossing that US officials say normally has about 100,000 visitors per day.

Department of Homeland Security Secretary Kirstjen Nielsen said in a statement that the port of entry was closed "to ensure public safety in response to large numbers of migrants seeking to enter the US illegally."

Some of the migrants tried to breach the border fencing and "sought to harm CBP personnel by throwing projectiles at them," the statement said.

Mexico's Interior Ministry added that almost 500 migrants had tried to cross the border in a "violent manner." Mexican authorities said they would deport anyone who tried to cross illegally.

US President Donald Trump has repeatedly threatened to close border crossings to prevent the migrant caravan from entering the US.

Although members of the caravan have been in Tijuana for several days, this is the first time that a significant group has massed at the border fence.

Migrants gather at the Mexico-US border after getting past a line of Mexican police at the Chaparral crossing in Tijuana.

The San Ysidro crossing is a large complex with multiple lanes of vehicle and pedestrian access points.

In recent days, Mexican authorities and others have worried about the economic effect of the United States closing down such an important crossing for trade and travellers.

Duncan Wood, the director of the Mexico Institute at the Wilson Centre in Washington, said in a statement that "the closing of the border is a drastic response to a serious incident but it is vital that calm heads prevail."

"Closing a border crossing like [San Ysidro] more than temporarily involves losses of many millions of dollars and severe disruption of commerce and life at the border," he added.

A Central American migrant is stopped by US agents who order him to go back to the Mexican side of the border, after a group of migrants got past Mexican police.

After starting in Honduras and travelling across Mexico, the first members of the caravan began arriving in Tijuana about two weeks ago.

In recent days, the group has grown to more than 8200, with about 7400 members in the border cities of Tijuana and Mexicali, according to Mexican authorities. Tijuana's mayor declared the situation a humanitarian crisis.

The bulk of the group has been camped out at a sports complex across a highway from the border fence. While a small portion of the caravan protested, thousands stayed behind in the sports complex.

US border officials have said they have a limited capacity to process asylum seekers, up to 100 per day. Asylum seekers waiting at the border said 40 per day were being let in on Saturday and Sunday. On Friday, 80 were allowed in.

For the past few days, the migrants planned the protest to express their frustration about the wait and the conditions where they're living, some of them painting signs asking Trump to let them in.

Mexican police run as they try to keep migrants from getting past the Chaparral border crossing in Tijuana, Mexico.

"Desperation has led some people to really believe that crossing is possible," said Alex Almendares, 22, a member of the caravan from Colon, Honduras. "The US has given us no response, and the situation at the shelter keeps getting worse."

The protest march headed toward one of the pedestrian crossings. Mexican police in riot gear blocked its way, and a scuffle broke out between police and two dozen protesters. After being rebuffed, the situation grew more chaotic, with some migrants running across a dry canal and others trying to cross in different places.

US authorities fired tear gas that wafted into Mexico and caused migrants to run from the fumes. No serious injuries were immediately reported.

As federal law enforcement officers, Border Patrol agents have broad latitude to use force if they think they are under attack or at risk of injury. An agent in Arizona who fired his service weapon through the border fence in response to rock throwers, killing a 16-year-old boy, was acquitted Wednesday on charges of involuntary manslaughter.

Maria Lousia Caceres, 42, and her son followed people who were running toward the fence.

"We thought it was a peaceful march today, but then I saw everyone running and I thought, 'This is it, God will touch Trump's heart,' " she said.

Caceres, a tortilla vendor from San Pedro Sula, Honduras, said she had fled her hometown and joined the caravan after gang members killed two of her brothers and burned down her house. She said she wants asylum in the US but really just "wants life to get better now."

Standing by the fence, when she realised there was no way to cross the border, she said she did not know what would happen next. "Now we wait," she added.