A warning has been issued that a massive migrant caravan is currently making its way through Mexico to the U.S. border; the largest in more than a year, up to 15,000 migrants are expected to join.

The New York Post reports the migrant families are primarily from Cuba, Haiti and Honduras. The groups started its journey to the U.S. on Sunday, “walking more than nine miles form the Mexican souther border city Tapachula to get to Alvaro Obregón.”

The group is the largest caravan since June of 2022. The Post notes that the strain on U.S. border security and resources is already in trouble. As many as 10,000 migrants were arrested each day at the southwest border this month, US Customs and Border Patrol officials say.

The total number of migrant encounters in December has also already surpassed 200,000, and the Mexican government has said it has detected about 680,000 migrants moving through the country in the first 11 months of 2023.

Last week, the US Customs and Border Patrol halted railway operations at international crossings into Texas to try to curb the massive migration into the country.

“CBP is continuing to surge all available resources to safely process migrants in response to increased levels of migrant encounters at the southwest border, fueled by smugglers peddling disinformation to prey on vulnerable individuals,” the agency said in a statement at the time.

“After observing a recent resurgence of smuggling organizations moving migrants through Mexico via freight trains, CBP is taking additional actions to surge personnel and address this concerning development, including in partnership with Mexican authorities.”

But Border Patrol agents say they have become overwhelmed by the surge in migrants, with the migrants outnumbering agents 200 to 1 at one Texas crossing.

The National Border Patrol Council said “agents are more than willing to sacrifice holidays to protect our fellow Americans, but what we are doing is not enforcing our laws; because of bad policy, our government is allowing cartels to control our border,” it said in a statement to NewsNation.

Federal officials are set to meet with their Mexican counterparts in Mexico City to stem the tide of migrants coming into the US.