And he emphasized that, as President Donald Trump has made clear, the USA will not allow a large group to enter the country illegally, and advised migrants to seek asylum in Mexico, where he said the government is offering migrants protection and employment authorization.
A new group of Central American migrants wade in mass across the Suchiate River, that connects Guatemala and Mexico, in Tecun Uman, Guatemala, Oct. 29, 2018. "He said that Mexican federal police and immigration agents were attacked with rocks, glass bottles and fireworks when migrants broke through a gate on the Mexican side of the border, but that none of the officers were armed with firearms or anything that could fire rubber bullets".
The U.S. military will be sending 5,000 support troops to the U.S. -Mexico border, the Pentagon announced on Monday. Others soaked themselves in the nearby Novillero river.Tensions from a long trek through searing heat with tenuous supplies of food and other goods spilled over Saturday night when a dispute in a food line devolved into a beating.
O'Shaughnessy is the first US military official to say how many active-duty troops will be involved with the operation.
Guatemalan riot police fired tear gas at the migrants on Sunday who, in desperation to continue their northward trek toward the USA border, responded by hurling stones and sticks, reports Efe news.
While one almost 4,000-person caravan is about 900 miles away from the US border as of Monday, another group that set out north from Central America later met resistance from Mexican police as they illegally broke through the border between Mexico and Guatemala.
Trump said the United States would build "tent cities" to house migrants seeking asylum, rather than releasing them while they await court decisions. He said border agents will act with the highest respect for the law and will treat people as humanely as possible. "We will continue to adjust the number and inform you of those".
The announcement during a Fox News interview came as the Pentagon announced it was deploying 5,200 active-duty troops to beef up security, and follows weeks of heated anti-migrant rhetoric from the president ahead of crucial midterm congressional elections next week. Others joined it in southern Mexico.
O'Shaughnessy said some soldiers would be armed although it was unclear who, beyond USA military police, might need those weapons.
Again, without providing evidence, he said there are "many gang members and some very bad people mixed into the caravan". They will include exactly how many forces are needed.
On Monday he warned that the military would be waiting.
Trump said anyone wanting to get into the United States must do so through the legal process.
Military personnel are legally prohibited from engaging in immigration enforcement. U.S. Transportation Command posted a video on its Facebook page Monday of a C-17 transport plane that it said was delivering Army equipment to the Southwest border in support of the operation.
The projected US deployment is already roughly the same size as the USA military contingent in Iraq.