President Trump issued a memorandum on Friday directing his administration to move quickly to bring an end to “catch and release,” the practice by which immigrants presenting themselves at the border without authorization are released from detention while waiting for their cases to be processed.

The directive does not, on its own, toughen immigration policy or take concrete steps to do so; it merely directs officials to report to the president about steps they are taking to “expeditiously end ‘catch and release’ practices.” But it is a symbolic move by Mr. Trump to use his executive action to solve a problem that he has bitterly complained Congress will not.

It also caps a week that began with the president offering tough talk on immigration and ended with his ordering the National Guard to patrol the southwestern border, a move formalized on Friday night when Defense Secretary Jim Mattis signed orders to deploy up to 4,000 troops.

“The safety and security of the American people is the president’s highest priority, and he will keep his promise to protect our country and to ensure that our laws are respected,” Sarah Huckabee Sanders, the White House press secretary, said in a statement announcing the memorandum.