TIJUANA, Mexico (AP) — Some Central American migrants, mostly men, tried to breach the border crossing between Tijuana, Mexico and California on Sunday, after pushing past a blockade of Mexican police standing guard near the international border crossing in a bid to pressure the U.S. to hear their asylum claims.

In response, U.S. border guards suspended crossings at the the San Ysidro port of entry in California and shot tear gas into Mexico, according to an AP reporter at the scene.

Mexico’s Milenio TV showed images of at least a few of the hundreds of migrants at the border tried to jump over the fence separating the two countries.

The migrants carried hand-painted American and Honduran flags and chanted: “We are not criminals! We are international workers!” The group mostly consisted of men, although some women pushed small children ahead in strollers.

U.S. Border Patrol 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 have been suspended at the San Ysidro port of entry at both the East and West facilities.

Southbound lanes into Mexico at the San Ysidro port of entry are currently closed. Updates will be provided. — CBP San Diego (@CBPSanDiego) November 25, 2018

In addition, northbound vehicle traffic processing at San Ysidro is currently suspended. Updates will be provided as they become available. — CBP San Diego (@CBPSanDiego) November 25, 2018

Pedestrian crossings at the San Ysidro port of entry are also suspended at both the East and West facility. — CBP San Diego (@CBPSanDiego) November 25, 2018

Migrants were enveloped with tear gas after U.S. agents shot the gas, according to an Associated Press reporter on the scene. Children were screaming and coughing in the mayhem.

Honduran migrant Ana Zuniga, 23, said she saw migrants open 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.

“We ran, but when you run the gas asphyxiates you more,” she told the AP while cradling her 3-year-old daughter Valery in her arms.

US Border Patrol has just launched tear gas into Mexico. Breeze carrying it hundreds of yards. Parents running away with choking toddlers. #migrantcaravan — Chris Sherman (@chrisshermanAP) November 25, 2018

Strong breeze carried US-launched teargas deeper into Mexico. Migrants ran for hundreds of yards before escaping the cloud. #migrantcaravan — Chris Sherman (@chrisshermanAP) November 25, 2018

US agents have fired another volley of tear gas into Mexico along the Tijuana River. Migrants retreating again. #migrantcaravan — Chris Sherman (@chrisshermanAP) November 25, 2018

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.

Some of the migrants who went forward Sunday called on each other to remain peaceful.

They appeared to easily pass through the Mexican police blockade without using violence.

A second line of Mexican police carrying plastic riot shields stood guard outside a Mexican customs and immigration plaza, where the migrants were headed.

That line of police installed tall steel panels behind them outside the Chaparral crossing on the Mexican side of the border, which completely blocked incoming traffic lanes to Mexico.

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 Gastlum 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.