Earlier in the day, President Donald Trump in a Twitter post instructed Nielsen to ensure members of a Central American caravan, reportedly traveling through Mexico towards the US border, are not allowed to enter the United States.
"DHS, in partnership with DOJ [Department of Justice], is taking a number of steps to ensure that all cases and claims are adjudicated promptly," Nielsen said. "For those seeking asylum, all individuals may be detained while their claims are adjudicated efficiently and expeditiously, and those found not to have a claim will be promptly removed from the United States."
The DHS chief also said the department continues to monitor the remnants of the "caravan" of individuals headed to the US southern border who seem bent on entering the United States illegally. Nielsen urged all immigrants seeking asylum to seek protection in the first "safe country" they enter which includes Mexico.
Trump had threatened the caravan in Twitter messages multiple times over the past few days and has also signed a proclamation requesting that governors of states bordering Mexico send National Guard troops to patrol the border. Organizers of the caravan announced early this month that they would end their journey in Mexico City, because the size of the group made it too difficult to travel, according to media reports.