The Senate Appropriations Committee will hold a hearing Thursday on President Obama’s request for emergency funds to deal with the flood of migrant children at the U.S. border.
The president is expected this week to make a detailed request to Congress for more than $2 billion to respond to the surge in unaccompanied children and other migrants from Central America.
Homeland Security Secretary Jeh Johnson said on Sunday that the Obama administration will "stem the tide" of migrants at the border.
He blamed deteriorating conditions in Honduras, El Salvador and Guatemala for the spike.
"The push factor is what's driving this recent influx," he said.
Democrats and Republicans have been critical of the Obama administration's response to the border crisis.
Health and Human Services Secretary Sylvia Mathews Burwell and State Department counselor Thomas Shannon Jr. also are slated to testify on Thursday.
Sen. Lindsay Graham (R-S.C.) was among several Republican and Democratic lawmakers on Sunday to say that young children crossing the border must be sent back to their home countries to dissuade others from attempting the trip.
Rep. Raúl Labrador (R-Idaho) argued Sunday that anyone crossing the southern border should be immediately deported.
Democratic Rep. Henry Cuellar, who represents a border district in Texas, said Sunday that the administration failed to anticipate a predictable crisis and remains "one step behind" in addressing it.