MEXICO CITY • Thousands of Central American migrants traveling in a caravan arrived in the Mexican capital Monday and began to fill up a sports stadium, still hundreds of miles from their goal of reaching the U.S. a day before midterm elections in which President Donald Trump has made their journey a central campaign issue.

By afternoon 2,000 or more had arrived at the Jesus Martinez stadium, which has a capacity of about three times that, and eagerly began sifting through donations of clothes, gave themselves sponge baths, lunched on chicken and rice under the shade of tents and picked up thin mattresses to hunker down for the night.

Many went to medical tents to get treatment for blistered and aching feet, illness and other maladies. “Since we got here, we have not stopped,” said Tania Escobar, a nurse with Mexico City’s public health department.

Melvin Figueroa, a 32-year-old from Tegucigalpa, Honduras, was traveling with his pregnant wife and two children, 6 and 8.

He brought the 6-year-old girl to the tent because her eyes were irritated and “she throws up everything she eats.”

Several thousand more migrants were trudging along the highway between the city of Puebla and the capital, catching a lift from passing vehicles when possible.

Nashieli Ramirez, ombudsman for the city’s human rights commission, said the city was preparing to accommodate as many as 5,000 migrants from the lead caravan and several smaller ones hundreds of miles behind it.

“We have the space in terms of humanitarian help,” Ramirez said.