US President Donald Trump has threatened to use military force to completely close the US-Mexico border.
The warning, via a series of tweets on Thursday, comes as a new caravan of more than 3,000 migrants from El Salvador, Honduras and Guatemala heads north.Mr Trump has already threatened to cut all aid payments to the three countries over illegal immigration.
The group says they are fleeing violence and poverty.
"In addition to stopping all payments to these countries, which seem to have almost no control over their population, I must, in the strongest of terms, ask Mexico to stop this onslaught - and if unable to do so I will call up the U.S. Military and CLOSE OUR SOUTHERN BORDER!," Mr Trump wrote.
Why does it concern Trump?
The group of Central American migrants has made its intentions clear: they are heading to the US.
Since he was on the campaign trail, Mr Trump has lambasted illegal immigrants, and this latest caravan comes after a major crackdown on migrants heading over the Mexican border.
Changes to detention rules saw thousands of migrant children detained and separated from their parents earlier this year, sparking national and international condemnation.
The president's threats also come just weeks before the mid-term elections on 6 November, which could see Democrats unseating Republicans on Capitol Hill.
Read also:Melania Trump says President Trump's alleged affairs are 'not concern and focus of mine'
Mr Trump's recent comments are probably an effort to bolster support among his base by cracking down on migration.
Source: bbc