President Donald Trump's administration has begun detaining parents and relatives who they suspect paid to have children brought illegally into the United States, officials said Friday.

Criminally prosecuting adults who ask smugglers to bring minor relatives here was first floated in a memorandum signed by Homeland Security Secretary John Kelly in February, but enforcement thus far has been rumored, not confirmed.

In a statement Friday, an Immigration and Customs Enforcement spokeswoman said the enforcement action was part of a broader “surge initiative” to identify and arrest people involved in human smuggling operations. She declined to elaborate on how many relatives have been arrested, what they are being charged with or when the operation began, how long it will last, and how many people it will target.