Border guards used tear gas on a group of around 500 migrants who were attempting to storm the border in Tijuana, Mexico.
US officials have also completely closed the border to pedestrians and vehicles.
The caravan’s plight has become highly politicised in recent weeks.
U.S. Customs and Border Protection agency fires tear gas at migrants heading toward crossing on U.S.-Mexico border https://t.co/jH9QlSqszN [Corrects who fired the tear gas.]
— The New York Times (@nytimes) November 26, 2018
Children seen running from tear gas cloud at the border crossing
One witness reported a member of the migrant group made “a small hole in concertina wire at a gap on the Mexican side of a levee,” in an attempt to get onto US land.
The migrants were then met with border agents firing tear gas to drive them back. Children were seen screaming as they fled the cloud of tear gas.
Other images showed border officials firing rubber bullets at members of the caravan and other migrants trying to scale the fence at the border.
Earlier in the day, members of the caravan had been holding a peaceful protest to appeal to the US to expedite their asylum claims but some broke away from the group when they saw an opportunity to cross the border.
The migrant group has travelled more than 4,000km (2,500 miles) from Central America. They say they are fleeing persecution and poverty in El Salvador, Guatemala and Honduras.
On the morning of 25 November local time, several hundred migrants passed through a blockade of Mexican police without using violence.
On 23 November, Tijuana Mayor Juan Manuel Gastelum declared a humanitarian crisis and said his city was being overwhelmed by the influx of immigrants. Around 5,000 immigrants had been camping in a sports centre in the city.
US Customs and Border Protection has closed road and pedestrian bridges in both directions at the San Ysidro port of entry, one of the largest land border crossings between San Diego and Tijuana, Mexico. https://t.co/rM8oMC5Vnk pic.twitter.com/nqUFpZ0cPR
— CNN Newsroom (@CNNnewsroom) November 25, 2018
More US border officials have been sent to the San Ysidro entry point
The US Customs and Border Protection (CBP) has stationed more officials at San Ysidro, which is the busiest land port of entry in the Western Hemisphere.
Kirstjen Nielsen, Secretary of Homeland Security, said some of the migrants threw projectiles at CBP officials.
“DHS (Department of Homeland Security) will not tolerate this type of lawlessness and will not hesitate to shut down ports of entry for security and public safety reasons,” she said.
“We will also seek to prosecute to the fullest extent of the law anyone who destroys federal property, endangers our front-line operators, or violates our nation’s sovereignty.”
In a statement, the CBP said it suspended port of entry operations out of a concern that more groups would splinter off from the main caravan and rush the border.
Would be very SMART if Mexico would stop the Caravans long before they get to our Southern Border, or if originating countries would not let them form (it is a way they get certain people out of their country and dump in U.S. No longer). Dems created this problem. No crossings!
— Donald J. Trump (@realDonaldTrump) November 25, 2018
Trump responds to the latest developments
Donald Trump has vowed to keep the entire group out of the US until courts have ruled on their case.
“Would be very SMART if Mexico would stop the Caravans long before they get to our Southern Border,” he wrote on Twitter. “Or if originating countries would not let them form (it is a way they get certain people out of their country and dump in U.S. No longer). Dems created this problem. No crossings!”
Mexico’s Interior Ministry said its officials were able to contain a group of about 500 migrants tried to breach the border “in a violent way.” It promised to “immediately deport” anyone who violently attempted to cross the fence.
Mexico has already turned back 11,000 Central American migrants since 19 October, its Interior Ministry said. It added that 1,906 of those turned back were members of caravans.
The total number of Central Americans sent back to their countries of origin by the end of 2018 is set to top 100,000.