Washington (AFP) - US President Donald Trump on Thursday said he would send thousands of National Guard troops to the southern border, amid a widening spat with his Mexican counterpart Enrique Pena Nieto.
The anti-immigration president said the National Guard deployment would range from 2,000 to 4,000 troops, and he would "probably" keep many personnel on the border until his wall is built -- spelling out a lengthy mission.
The announcement capped a day of developments in Mexico, where the caravan of Central American migrants whose trek toward the United States had infuriated Trump began breaking up.
And Mexican President Pena Nieto said Trump's "threatening attitudes and a lack of respect" were unjustified.
The decision to send National Guard forces to the border on an open-ended deployment also raised questions about who will fund the mission.
The Pentagon could not say where the money would come from and Trump admitted the White House was still "looking at" costs.
If 4,000 troops were deployed, that would be about double what the United States currently has in Syria and about half as many as the number of US troops in Iraq.
The National Guard has previously been deployed to help patrol the southern border, including in 2010 under former president Barack Obama, and from 2006-2008 under George W. Bush.Both deployments were limited to around a year.
In a sign of the Pentagon's unpreparedness for Trump's initial border directive, which came Tuesday, just hours before the commander-in-chief announced the size of the troop deployment, military officials said they had no idea how many Guardsmen would go to the border, whether they will be armed, when they will deploy and how long they will be there.
'Negative rhetoric'
The caravan in Mexico, which numbered more than 1,000 Hondurans, Salvadorans and Nicaraguans, began breaking up after the activists organizing it said it had abandoned its goal of reaching the US border and would end its activities with a rally in Mexico City.
Trump had threatened to axe what he called Mexico's "cash cow," the North American Free Trade Agreement (NAFTA), if the Mexican authorities did not stop the migrants.
The ongoing talks on modernizing NAFTA have also strained ties between the two countries, as well as Canada, the third member of the agreement -- though the three countries have recently indicated they are close to reaching a new deal.
"We are convinced that, by coming to agreements as friends, partners and good neighbors, both countries will fare better than if we confront each other," Pena Nieto said.
"We stand ready to negotiate, certainly, but always based on mutual respect."
Still, Pena Nieto vowed Mexico would always stand up for itself and suggested Trump is jeopardizing the two countries' relationship for domestic political gain.
"If your recent statements are caused by your frustration over internal political matters, your laws or your Congress, take it up with them, not the Mexican people.We are not going to allow negative rhetoric to define our actions," he said in a national address.
Mexican ties have been strained since Trump won office on the back of a campaign heavy on anti-Mexican rhetoric.
Pena Nieto has twice canceled plans to visit Washington after tense phone calls with Trump in which the Republican president refused to back down from his insistence that Mexico pay for his planned border wall.
'Like a war'
Trump meanwhile returned to the theme that underpinned his presidential campaign -- which he opened by vowing to keep out Mexican "rapists."
"Remember my opening remarks at Trump Tower, when I opened everyone said 'Oh, he was so tough.' I used the word rape," Trump said during a meandering monologue on migration at an event in West Virginia.
"And yesterday it came out that, this journey coming up, women are raped at levels nobody's ever seen before," he added without giving further details.
Trump also went back to a campaign staple of urging "rough justice" for people who come to America illegally and boasted immigration officials were "so much tougher" than those they pursue.
"They're grabbing them by the necks and throwing them into paddy wagons," he said.
"People are clapping and screaming, their townsmen liberated -- it's like a war."
