>> President Trump stepping up threats, Thursday, warning he might call up the US Military and shut down the southern border in order to stop a large group of migrants from reaching the United States. In a series of tweets, Thursday, Trump pointed a finger directly at Mexico. Quote, I must, in the strongest of terms, ask Mexico to stop this onslaught.
And if unable to do so, I will call up the US Military and close our southern border. Floating the idea of military involvement, setting off a war of words between White House Chief of Staff, John Kelly, and National Security Advisor, John Bolton. Reuters' White House Correspondent, Steve Holland.
>> The details are a bit murky, but we're told it was about illegal immigration. This took place outside the Oval Office. It was a tense exchange, as it was described to us. Things got heated. There was a debate over the performance of the Homeland Security Secretary, Kirstjen Nielsen.
And at the root of this is how to handle this cross-border problem that we have.>> Trump's fiery threats, which include cutting off aid to the region, hasn't stopped the caravan from growing since it started heading north on Saturday.>> Through necessity and because of the economic crisis caused by the government.
That's why we have to migrate.>> Already into the thousands, the group has grown larger as more Hondurans defy their own government and join the trek making its way through Guatemala. Crossing through the lush jungle, navigating through water and challenging terrain, some even overcome by heat during the long journey.
Guatemala's President dismissed Trump's warning that financial aid to Central America will be stopped if the caravan is allowed to continue. Trump says halting this mass migration is even more of a priority than a new trade deal with Mexico.