Borders USA with Mexico “not open,” the U.S. Secretary of Homeland Security warned today as his country prepares to lift a pandemic measure and restrict entry over the next few hours immigrants on American soil.

“I want to be clear: our borders are not wide open. People who cross the border irregularly and without any legal reason to stay (…) will be deported immediately,” said Alejandro Mallorcas at the press conference he gave.

Mallorcas said that some border areas are already seeing an influx of people wishing to enter the US, and noted that it will take some time for the US administration’s new approach to immigration to work and bear fruit. He noted that immigrant families who do not meet the asylum criteria will be repatriated within 30 days.

The arrival of immigrants has already increased. In recent days, the Customs and Border Protection (CBP) has been holding up to 28,000 immigrants at its facilities, more than it can handle, according to two federal officials who spoke on condition of anonymity and the Border Patrol Association. The detention centers where most of them are concentrated are the Rio Grande Valley in Texas and two others in Arizona, according to Border Patrol President Brandon Judd. This week, the number of identified persons illegally crossing the border exceeded 10,000 per day. Judd said that due to the large number of arrivals, officers are releasing some migrants without issuing them a subpoena where they can apply for asylum, but simply telling them to report to the immigration office later.

In Yuma, Arizona, hundreds of migrants have been waiting in the freezing cold since dawn at an opening in the border fence to surrender to US agents. Some, like Giovana Gomez, 40, from Colombia, heard about the change in US policy and decided to try their luck now. “In my country, they say that immigration will only be allowed until May 11, so we are in a race against time. It was not easy,” he said.