Mexico arrests 98 people as march turns chaotic after US agents fired tear gas at migrants and refugees near border.

Mexico pledged on Sunday to increase security near its border crossings and said it will deport some of the 500 asylum seekers who attempted to breach the United States border.

Those who tried to “violently” and “illegally” enter the US would be deported immediately, the Mexican interior ministry said on Sunday.

“We are going to act and proceed to their deportation,” Mexico’s Interior Minister Alfonso Navarrete told the Milenio television network. “Far from helping the caravan, they are hurting it.”

More than 5,000 migrants and refugees have arrived in Tijuana in recent weeks as part of a caravan, dubbed the Central American exodus. Many have told Al Jazeera they are fleeing violence, poverty and political persecution.

Sunday’s announcement came after a peaceful march in Tijuana devolved into chaos when US border agents fired tear gas at migrants and refugees, including children, in attempt to stop a small group who tried to breach the border.

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The US closed the San Ysidro crossing point between Tijuana, Mexico and San Diego, California for several hours in response.

Secretary of the US Department of Homeland Security (DHS) Kirstjen Nielsen later issued a statement accusing the migrants of seeking to harm border patrol personnel “by throwing projectiles at them”.

“As I have continually stated, 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, adding the US would “seek to prosecute” offenders.

Immigration Authority Director Gerardo Garcia told television channel Televisa that 98 people had been arrested and were in process of deportation as of Sunday night.

In the US, Rodney Scott, chief US Border Patrol agent in San Diego, said authorities had arrested 42 people.

A family run away from tear gas in front of the border wall between the USand Mexico in Tijuana [Kim Kyung-Hoon/Reuters]

Videos posted on Twitter showed large numbers of migrants and refugees dashing across a shallow concrete waterway towards the border. They also show the group scrambling as tear gas is thrown from US authorities. Local media reported a number of injuries.

The developments on Sunday come as frustration grows in Tijuana over the long wait times for processing asylum claims. The number the US processes each day varies widely, and rights groups have accused US authorities of stalling the processing, allegations US Customs and Border Protection denies.

Trump went further on Monday, saying Mexico should send the Central Americans, mostly Hondurans, back to their home countries.

Meanwhile, Mexico’s incoming government has denied reports that it has agreed to allow asylum seekers to wait in the country while their claims move through US immigration courts.