President Obama will ask Congress to provide more than $2 billion in new funds to control the surge of illegal Central American migrants at the South Texas border, and to grant broader powers for immigration officials to speed deportations of children caught crossing without their parents, White House officials said on Saturday.

Mr. Obama will send a letter on Monday to alert Congress that he will seek an emergency appropriation for rapidly expanding border enforcement actions and humanitarian assistance programs to cope with the influx, which includes record numbers of unaccompanied minors and adults bringing children. The officials gave only a general estimate of the amount, saying the White House would send a detailed request for the funds when Congress returned after the Fourth of July recess that began Friday and ends July 7.

The president will also ask Congress to revise existing statutes to give the Homeland Security secretary, Jeh Johnson, new authorities to accelerate the screening and deportation of young unaccompanied migrants who are not from Mexico. Fast-track procedures are already in place to deport young migrants from Mexico because it shares a border with the United States.

Mr. Obama will also ask for tougher penalties for smugglers who bring children and other vulnerable migrants across the border illegally, the officials said.