HUEHUETAN, Mexico (Reuters) - Mexico’s military police on Saturday halted and turned back a caravan of up to 2,000 migrants from Africa, the Caribbean and Central America, hours after they embarked toward the United States, according to Reuters witnesses.

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The migrants had departed before dawn from Tapachula in the southern state of Chiapas near Guatemala despite an ongoing crackdown on migration on both sides of the U.S.-Mexico border.

The group, including people pushing children in strollers, proceeded on foot about 19 miles (30 km) before being apprehended on the road in Huehuetan in the afternoon.

Around 500 members of Mexico’s National Guard military police in helmets and tactical vests blocked the highway on both sides, according to a Reuters witness, and some pursued migrants who fled into neighboring fields.

Officials from Mexico’s national immigration institute detained most of the group, putting them on buses back to Tapachula. About 150 migrants decided to return on foot.

Activist Irineo Mujica of Pueblo Sin Fronteras, who accompanied the migrants, said only a small group opted to walk back on their own.

“The vast majority were taken to Tapachula, the caravan was dismantled,” he said in a video documenting the incident.

The scene was reminiscent of a string of caravans that left Central America a year ago, at one point ballooning into a group of 7,000 people in southern Mexico.

That en masse migration drew extensive media attention and triggered a crisis with U.S. President Donald Trump, who called the caravans an “invasion” and demanded Mexico do more to halt their progress.

The Mexican government in June struck a deal with the United States vowing to significantly curb U.S.-bound migration in exchange for averting U.S. tariffs on Mexican exports.

Arrests at the U.S.-Mexico border fell in September for the fourth month in a row, after record high crossings this Spring, and the Trump administration credited cooperation from Mexico and Central American countries for the sustained drop.