Former President Donald Trump on Wednesday said a caravan of Central American and Caribbean migrants “must be stopped” before it reaches the U.S.-Mexico border.

Reuters reported that hundreds of migrants, a majority of whom are families with young children, were trekking across Mexico. A witness estimated that about 2,000 migrants on Tuesday were resting and receiving medical attention in the southern Mexican state of Chiapas before resuming their journey north.

“I hope everyone is watching the MASSIVE Caravan pouring through Mexico and headed to our Country,” Trump said in a statement released by his Save America PAC and tweeted by spokesperson Liz Harrington.

“This must be stopped before they reach our Border, or before. Just nine months ago, we had the strongest Border in our Nation’s history. This should have never happened!”

Trump also released a statement concerning the caravan on Sunday.

“The largest caravan in history is coming towards us, and we are totally unprepared and doing nothing about it,” Trump said. “Complete the wall and get tough. Our Country is being systematically destroyed before our very eyes!”

In a separate statement Sunday, Trump said the U.S. was “being poisoned with the millions of people that are illegally flowing through our Borders, in most cases not even questioned or stopped.”

“Many are criminals from the emptied prisons of other countries, most of these are very dangerous people,” he said. “The first thing that should be done, and it can be done quickly, is FINISH THE WALL,” he wrote. “A deal must be made with Mexico, where Mexico serves as a 2,000 mile barrier, not a launching pad for the illegals that are coming in.”

Most of the migrants in the latest caravan are from Honduras and El Salvador, the Associated Press reported.

Unlike previous marches, the one that started Saturday from Tapachula did not include as many Haitian migrants, thousands of whom reached the southern border in September.