"Our country is facing a national security and humanitarian crisis along our southern border," House Speaker John Boehner (R-Ohio) wrote to the president on Friday.
"The policies of your administration have directly resulted in the belief by these immigrants that once they reach U.S. soil, they will be able to stay here indefinitely.
"There are several steps that we call on you and your administration to take immediately to enforce our laws, stem the tide of migrants, protect the victims, and ensure that these individuals are dealt with in a humane manner that is consistent with American ideals of compassion and family unity."
Boehner said in addition to deploying the National Guard, the administration should arrange for "apprehended migrants" to be "promptly returned" to their home countries; and he wants additional personnel sent to assist in their removal.
"The safety of these migrant children is a matter of paramount importance," Boehner said. "It is our duty and obligation to enforce the laws of our country while protecting the most vulnerable and ensuring they are healthy and well protected."
Boehner said the Homeland Security Department "must find a way to ensure that apprehended adults and their family members do in fact appear for their deportation hearings."
Boehner also urged Obama to "work with the Congress to develop a long-term strategy to secure our borders and ensure the integrity of our immigration laws."
President Obama is pressing the Republican-led House to pass an immigration reform bill that would give millions of illegal aliens provisional residency in this country that would set them on an eventual path to citizenship.
The bill -- passed last year by the Senate -- requires certain border-security goals to be met before other provisions are implemented, but Boehner repeatedly has said that Republicans don't trust the Obama administration to do what the bill says.
Obama has taken it upon himself to decide how current U.S. immigration laws are enforced. Two years ago, he signed a memo that defers deportation for certain foreigners who were brought to this country illegally as children.
And before that, the Obama administration adopted a policy of "prosecutorial discretion" in determining which illegal aliens should be prioritized for deportation. Critics called it "backdoor amnesty."
The recent mass influx of impoverished children from Central America has elevated border security to a crisis situation.