TECUN UMAN, Guatemala | Hundreds of Central Americans following in the footsteps of a thousands-strong migrant caravan currently making its way toward the U.S. border crossed a river from Guatemala into Mexico on Monday, defying a significant Federal Police presence deployed to patrol that country’s southern frontier.

A migrant raises his fist as he nears the Mexican side of the the Suchiate River, that connects Guatemala and Mexico, Monday, Oct. 29, 2018. (AP Photo/Santiago Billy)

The migrants waded in large groups through the Suchiate River.  Once on the Mexican side the migrants were surrounded and escorted by  officers. The scene at the riverbank followed a violent exchange that occurred on the bridge over the river Sunday night, when migrants threw rocks and used sticks against police. One migrant died from a head wound during the clash, but the cause was unclear.

At the same time, first caravan of nearly 4,000 migrants resumed its advance, still at least 1,000 miles or farther from their goal of reaching the United States as the Pentagon announced it would send 5,200 active-duty troops to “harden” the U.S.-Mexico border. There are already more than 2,000 National Guard troops providing assistance at the border.

The caravan currently has about 4,000 people, but that number has been shrinking. Earlier this year, only about 200 from a caravan of some 1,000 migrants reached the Tijuana-San Diego frontier.

The Pentagon announcement comes as President Donald Trump has been focusing on the caravan to stir up his base a week before midterm elections. On Monday he tweeted: “This is an invasion of our Country and our Military is waiting for you!”

Earlier in the day, members of the caravan strung out along the highway outside the city of Tapanatepec, some waiting for rides while others plodded toward their goal for the day: Niltepec, about 34 road miles (54 kilometers) to the northwest. Federal Police patrols drove slowly alongside encouraging them to stay on the shoulder.