"We have not received any guidance on any additional support required, but we certainly remain postured," Manning said, as quoted by Inside Defense.
22 October 2018, 16:18 GMT
Manning confirmed that 2,100 National Guard troops are already stationed along the southern US border, the report said.
In a series of tweets earlier on Monday, President Donald Trump said he had alerted the US military and Customs and Border Protection of a national emergency after Mexico was unable to stop the caravan.
The caravan, which the United Nations has said is made up of more than 7,200 Central Americans, has crossed into Mexico en route toward the US border, where the migrants hope to gain asylum.
