TIJUANA, MEXICO - NOVEMBER 24:  An aerial view of the temporary shelter set up for members of the 'migrant caravan', with a section of the U.S.-Mexico border barrier visible (TOP R),  on November 24, 2018 in Tijuana, Mexico. Around 6,000 migrants from Central America have arrived in the city with the mayor of Tijuana declaring the situation a 'humanitarian crisis'. Most migrants in the caravan say they plan to petition for asylum in the U.S. The incoming government in Mexico will reportedly support a new Trump administration policy requiring migrants asking for asylum in the U.S. to remain in Mexico while their cases are processed.
Inside the migrant camp at the border
02:48 - Source: CNN
CNN  — 

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.

A migrant, part of a caravan of thousands from Central America trying to reach the United States, covers his face after U.S. Customs and Border Protection (CBP) throw tear gas to the Mexican side of the fence as they prepared to cross it illegally, in Tijuana, Mexico, January 1, 2019.   REUTERS/Mohammed Salem

Some of the migrants threw rocks as others lifted children over the razor-edged wire late Monday in the San Diego sector, the agency said a statement, which was based on initial reports. The confrontation continued into the early hours of Tuesday morning.

One image distributed by Reuters shows a man covering his mouth as he is surrounded by smoke. Another shows people going over the wall as armed agents stand on the US side.

Border Patrol agents hold their guns as migrants try to go over the border fence near Tijuana, Mexico.

About 150 migrants approached the fence, but about one-third of the group members turned back into Mexico when they saw Border Patrol agents, CBP estimated.

A migrant is lowered toward concertina wire on the US side of the border fence.

Others tried to enter the United States by going over or under the fence. The agency said teenagers wrapped in jackets, blankets or mats were put over the wire, as were “toddler-sized children.”

“Once again we have had a violent mob of migrants attempt to enter the United States illegally by attacking our agents with projectiles,” said Katie Waldman, a spokeswoman for the Department of Homeland Security. “As has happened before – in this and previous administrations – our personnel used the minimum force necessary to defend themselves, defend our border, and restore order.”

CNN has reached out to Families Belong Together, an advocacy group that works with migrants at the border, but didn’t get an immediate response.

Waldman said there were no reported injuries among the people throwing rocks. She called on Congress to act on funding for a border wall, amend the Trafficking Victims Protection Reauthorization Act, and end the Flores settlement agreement.

People flee after US agents employed gas and smoke at the border with Mexico.

Twenty-five people were apprehended, CBP said, without elaborating about where the detainees were sent. The agency said an internal investigation is underway.

A man looks through the fence as he and others prepare to cross it illegally on Monday.

The incident comes a little more than a month after a similar incident in which agents fired tear gas at migrants, igniting anger, debate and concern. The group included mothers and children, and a photo of Maria Lila Meza Castro and her kids captured national attention. They were later allowed into the country to await asylum hearings.