The border crossing at the San Ysidro port of entry was closed to vehicle and pedestrian traffic for hours Sunday amid the conflict, but had fully reopened by shortly after 5 p.m.
Earlier in the morning, a group of Central Americans staged a peaceful march to appeal for the U.S. to speed up the asylum claims process, but their demonstration devolved as they neared the crossing with the U.S. and some saw an opportunity to breach the border.
U.S. agents shot several rounds of gas, according to an Associated Press reporter on the scene, after migrants attempted to penetrate several points along the border. Migrants sought to squeeze through gaps in wire, climb over fences and peel back metal sheeting to enter.
Children screamed and coughed in the mayhem of the tear gas. Fumes were carried by the wind toward people who were hundreds of feet away, not attempting to enter the U.S.
Yards away on the U.S. side, shoppers streamed in and out of an outlet mall.
Honduran Ana Zuniga, 23, also said she saw migrants opening a small hole in concertina wire at a gap on the Mexican side of a levee, at which point U.S. agents fired tear gas at them.
Children screamed and coughed. Fumes were carried by the wind toward people who were hundreds of feet away.
"We ran, but when you run the gas asphyxiates you more," Zuniga told the AP while cradling her 3-year-old daughter Valery in her arms.
Mexico's Interior Ministry said around 500 migrants tried to "violently" enter the U.S.
The ministry said in a statement it would immediately deport those people and would reinforce security.
As the chaos unfolded, shoppers just yards away on the U.S. side streamed in and out of an outlet mall.
Throughout the day, U.S. Customs and Border Protection helicopters flew overhead, while U.S. agents held vigil on foot beyond the wire fence in California. The Border Patrol office in San Diego said via Twitter that pedestrian crossings were suspended at the San Ysidro port of entry at both the East and West facilities. All northbound and southbound traffic was halted.
Homeland Security SecretaryKirstjenNielsen said in a statement that U.S. authorities will continue to have a "robust" presence along the Southwest border and that they will prosecute anyone who damages federal property or violates U.S. sovereignty.
"DHS 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.
More than 5,000 migrants have been camped in and around a sports complex in Tijuana after making their way through Mexico in recent weeks via caravan. Many hope to apply for asylum in the U.S., but agents at the San Ysidro entry point are processing fewer than 100 asylum petitions a day.
Irineo Mujica, who has accompanied the migrants for weeks as part of the aid group Pueblo Sin Fronteras, said the aim of Sunday's march toward the U.S. border was to make the migrants' plight more visible to the governments of Mexico and the U.S.
"We can't have all these people here," Mujica told The Associated Press.
Tijuana Mayor Juan Manuel Gastelum on Friday declared a humanitarian crisis in his border city of 1.6 million, which he says is struggling to accommodate the crush of migrants.
U.S. President Donald Trump took to Twitter Sunday to express his displeasure with the caravans in Mexico.
"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)," he wrote.
Mexico's Interior Ministry said Sunday the country has sent 11,000 Central Americans back to their countries of origin since Oct. 19, when the first caravan entered the country. It said that 1,906 of those who have returned were members of the recent caravans.
Mexico is on track to send a total of around 100,000 Central Americans back home by the end of this year.