US Customs and Border Protection says it is investigating an incident at the California border with Mexico, in which agents used tear gas, pepper spray and smoke as more than 100 migrants tried to enter the country illegally.
In late November, also in the Tijuana area, USA border officers used tear gas and rubber bullets when about 500 men, women and children scrambled over a rusted metal fence and surged into a concrete riverbed before they encountered a second fence.
Customs and Border Protection agents fired tear gas after migrants from a migrant caravan hurled rocks at them.
Members of the group who spoke with AP said they arrived last month with a caravan which set out from Honduras.
"No agents witnessed any of the migrants at the fence line, including children, experiencing effects of the chemical agents, which were targeted at the rock throwers further away", the statement said.
U.S. border patrol agents used tear gas to keep the group from approaching the crossing line.
American authorities fired tear gas across the border into Mexico during a unsafe and chaotic situation in the early hours of 2019, officals say.
Clouds of the noxious gas could be seen wafting up from around the fence at the border, and one migrant picked up a canister and threw it back across the border into United States territory.
In footage provided by Reuters, a man is seen picking up and throwing a tear gas canister back over the barrier while a group of Spanish-speaking migrants cheers and whoops loudly. The agency said small children were also being put over the fence, adding the migrants were "having difficulty accomplishing the task in a safe manner".
A spokeswoman for the Department of Homeland Security claims the migrants were "a violent mob" who attacked USA agents with projectiles.
Thousands of Central American migrants have been camping at shelters in Tijuana since arriving in November after traveling in caravans across Mexico to reach the US border, where many have hoped to request asylum.
Jan 1, 2019, 10 p.m.: This story was updated to include a statement from a Department of Homeland Security spokesperson.
Some 25 people were arrested, including two teenagers, CBP said.
The migrant caravan left Central America in October and travelled 4,300km (2,600 miles) to Tijuana in the hope of reaching the U.S. and requesting asylum.
Trump refused to back down on his border wall project, despite it being the cause a partial government shutdown that has continued into its 11th day.
Trump used the caravan to stir up fear of immigrants as he pressed his drive to build a wall on the border.