Central American immigrants get on the so-called La Bestia (The Beast) cargo train, in an attempt to reach the Mexico-US border, in Arriaga, Chiapas state, Mexico on July 16, 2014
Washington (AFP) - The arrival of huge numbers of unaccompanied Central American children at the southern US border has overwhelmed authorities in the United States lacking the financial and legal means to curb the illegal influx.
President Barack Obama has insisted new arrivals will be sent home, but it remains unclear how much that has done to stem the flow -- although officials say the number of apprehended child migrants has decreased recently.
Scrambling to address the humanitarian crisis, US lawmakers introduced a plan last week to speed repatriation of the youths to their home countries.
The White House said a flight deporting 40 women and children back to Honduras served as a "signal" that new illegal immigrants were not welcome.
On Friday, Obama meets with the presidents of El Salvador, Guatemala and Honduras to collaborate on ways to prevent young Central Americans from taking the perilous journey overland through Mexico.
- Unprecedented wave -
More than 57,000 unaccompanied minors, from infants to 17-year-olds, were apprehended crossing into the United States between October 1 and June 30.
US officials predict 90,000 by the end of September, compared with 39,000 in all of 2013, 25,000 in 2012 and 16,000 in 2011.
In 2015, the government predicts, 145,000 children will be apprehended.
The total number of undocumented adult and child immigrants arrested at the border reached a peak of 1.2 million in 2005. It dropped to 328,000 in 2011 before rising to 414,000 last year.
- Unaccompanied minors -
Only recently, they were arriving at the rate of 200 to 250 per day, Homeland Security Secretary Jeh Johnson told lawmakers on July 10.
But on Monday, the White House said such daily apprehensions have dropped to an average of 150.
If they are alone and do not hail from US border nations Mexico or Canada, authorities are required to provide them shelter and move them within 72 hours to housing where they can then receive medical care and legal aid services.
They spend 34 days on average in such housing before being released, in 85 percent of the cases to a relative already present in the United States.
They are then ordered to appear in immigration court where their cases are heard.
But about 2,000 children were still in detention centers operated by border patrol agents beyond the 72-hour limit.
Three emergency temporary shelters have been set up by the Department of Health and Human Services, on military bases in California, Oklahoma and Texas.
US officials told senators last week that authorities are spending $250 to $1,000 per child per day for housing and care.
- From where, to where? -
About three-quarters of the child migrants come from El Salvador, Guatemala and Honduras. The number of Honduran children apprehended at the US border spiked from 968 in 2009 to 15,000 this year.
The vast majority were arrested in the Rio Grande Valley in southern Texas.
And unlike in previous migration waves, "this population for the most part wants to be apprehended," Johnson told lawmakers. "They're not seeking to evade law enforcement."
The number of child migrants soared in previous years as well, with more than 100,000 per year between 2004 and 2006. But while the undocumented youths caught on the border then were overwhelmingly Mexican, most of them now come from Central America.
- Deporting children -
Until recently, only about 1,800 unaccompanied children were deported each year by US authorities, following rulings by immigration courts. Obama's Republican critics say that makes for good odds for parents sending their children to the US illegally.
Obama and Congress are considering amending an anti-trafficking law from 2008 in order to accelerate the deportations of migrants from non-border countries.
- Huge border -
The US and Mexico share a 1,950-mile (3,140-kilometer) frontier, one of the world's longest.
In Arizona, California and New Mexico, the border is defined almost entirely by barriers or fencing. But the Texas border with Mexico is formed by the Rio Grande and is much more porous. Arrests of undocumented immigrants are concentrated in the area around the city of McAllen, in southern Texas.
Sources: US Customs and Border Protection, Congressional testimony, Bipartisan Policy Center.