A caravan of migrants approaching the United States, carrying babies, suitcases and hope

TAPACHULA, Mexico – President Trump promises to stop a caravan of migrants from Central America headed to the US border. Mexican authorities stated that the caravan numbered more than 5,000 people, including women and children. Most of them come from Honduras, fleeing poverty and violence.

Border security is a hot topic for the president before the mid-term elections. He again addressed the caravan at a weekend campaign rally.

"I will close the border before they arrive in this country and I will bring our troops, not our reserves, and I will get our troops out," said Trump.

On Sunday, the caravan made a leap forward, carrying babies, suitcases and hope. Advocacy groups in Central America often organize these groups because travel alone is so dangerous. CBS News has seen people walk 100 degrees, sweaty and exhausted, while being determined to reach the US border, still more than 1,500 kilometers away.

In the migrant river, it is difficult for families to stay together.

CBS News correspondent Adriana Diaz met two sisters separated from their parents. A sister said in she was traveling with her mother and father, they separated and her sister took care of her. The woman who watched over the sisters told us that their mother had loaded a truck that disappeared into the crowd. They have since been reunited. The truck apparently left before the mother could board.

We found Karen Lanza looking for her son after his failure. He finally caught up, exhausted. They had been walking for 10 days.

To get here, most of the migrants crossed a river between Guatemala and Mexico.

Some entered legally by a bridge at the pass. Others, desperate, jumped off the bridge and crossed the border. We saw the federal police on stand-by but it did not stop the illegal passages.

When the migrants finally reached the city of Tapachula, it started to rain and everyone tried to go to the shelter. The children tried to make the most of the wet chaos. Esneyder Navila sought refuge under a tarpaulin. He is 16 years old, alone and has never been to school.

"Why did you leave?" Diaz asked him.

"Because of the violence, because there is no money," he said, adding that he simply wanted to have an education.

In the midst of crying babies and hastily prepared meals, we reconnected with Karen and her exhausted children who told us that she was considering turning around. She said her children must have been hungry, but they were never cold and did not sleep on the floor.

Migrants are on the move again today. Many Diaz said that they were not slowed down by President Trump's threats to use the military to prevent them from entering the United States.