Texas Governor Rick Perry is sending 1,000 National Guard troops to the US border with Mexico to protect against what he described as criminals, human traffickers and drug cartels.
Republican Rick Perry said he had to act because the federal government had failed to secure the border.
He said the troops would work alongside law enforcement.
The move comes after a surge of unaccompanied Central American children crossed the border illegally.
More than 57,000 children, many fleeing gang violence and extreme poverty at home, have crossed the border since October.
In a news conference, Rick Perry said criminals would see the influx of children as an opportunity to be exploited. And he said that more than 203,000 “criminal aliens” had been held in Texas jails since 2008.
Texas Governor Rick Perry is sending 1,000 National Guard troops to the US border with Mexico
“There can be no national security without border security, and Texans have paid too high a price for the federal government’s failure to secure our border,” said Rick Perry, who ran unsuccessfully for the Republican presidential nomination in 2012 and has been named as a possible contender in 2016.
“The action I am ordering today will tackle this crisis head-on by multiplying our efforts to combat the cartel activity, human traffickers and individual criminals who threaten the safety of people across Texas and America.”
The Texas National Guard deployment will cost the state of Texas as much as $12 million per month.
President Barack Obama, a Democrat, has called for comprehensive immigration reform that would provide some path to legal status for the millions of undocumented immigrants living in the US as well as strengthen security at the border.
In response to the recent flood of illegal-immigrant children, Barack Obama has asked Congress for $3.7 billion to hire extra immigration judges, provide drone surveillance of the border, and fund medical services. Republicans in Congress rejected the request.
In Texas, a spokesman for the Texas Democratic Party accused Rick Perry of “photo-op politics” that ignored the need for comprehensive immigration reform.
“Local law enforcement, elected officials, and faith and community leaders in the Rio Grande Valley have expressed concerned about militarizing the border, the need to create a short-term humanitarian solution, and solving the long-term need for comprehensive immigration reform,” Emmanuel Garcia said.
“Today, Governor Rick Perry ignored those voices.”
Undocumented immigrants are applying for the temporary right to live and work openly in the US, as a sweeping immigration policy reform takes effect.
Up to 1.7 million people could be eligible for the programme, unveiled in June by President Barack Obama amid pressure from Hispanic voters.
Republicans say Barack Obama has passed over Congress – and unemployed US citizens – with the programme.
The Latino vote could be important in November’s presidential election.
Most of the estimated 11.5 million undocumented immigrants in the US are from Latin America.
Illegal immigrants are getting their records in order as the Department of Homeland Security (DHS) starts accepting applications.
Undocumented immigrants are applying for the temporary right to live and work openly in the US, as a sweeping immigration policy reform takes effect
In an internal document, DHS officials estimated 1.04 million people would apply in the first year.
The Migration Policy Institute and the Pew Hispanic Center have estimated as many as 1.7 million people could be eligible under the programme.
The administration’s plan is to stop deporting many illegal immigrants who were brought to the US as children.
To be eligible, immigrants must prove they arrived in the US before they turned 16, are 30 or younger, have been living here at least five years and are in school or graduated or served in the military.
They also cannot have been convicted of certain crimes.
The measure has echoes of the so-called Dream Act, which offered permanent residency to young undocumented immigrants, but failed to pass after years of congressional stalemate.
“Childhood arrivals who meet the guidelines and whose cases are deferred will now be able to live without fear of removal, and be able to more fully contribute their talents to our great nation,” said Alejandro Mayorkas, head of US Citizenship and Immigration Services.
But conservatives accused Barack Obama of political pandering as he and Republican White House rival Mitt Romney compete for the Hispanic voting bloc ahead of November’s elections.
Republican House Judiciary Committee Chairman Lamar Smith said on Tuesday: “While potentially millions of illegal immigrants will be permitted to compete with American workers for scarce jobs, there seems to be little if any mechanism in place for vetting fraudulent applications and documentation submitted by illegal immigrants.”
The Obama administration detailed on Tuesday what documents illegal immigrants need to qualify for the programme.
The paperwork for the programme can be downloaded from the immigration services website.
Applicants must pay a $465 fee and provide proof of identity and eligibility.
This could include a passport or birth certificate, school transcripts, medical and financial records, military service records and, in some cases, multiple sworn affidavits.
A decision on each application could take several months, and immigrants have been warned not to leave the country while their paperwork is being processed.
Advocacy groups are planning to run events this week to help migrants get their paperwork in order.
Greek police has announced that more than 1,600 illegal immigrants will be deported following a major crackdown in Athens in recent days.
More than 6,000 people have been detained, though most were released.
Public Order Minister Nikos Dendias defended the crackdown. He said Greece’s economic plight meant it could not afford an “invasion of immigrants”.
He called the immigration issue a “bomb at the foundations of the society and of the state”.
“Unless we create the proper structure to handle immigration, then we will fall apart,” he said.
Greek police has announced that more than 1,600 illegal immigrants will be deported following a major crackdown in Athens in recent days
Some 88 illegal immigrants were sent back to Pakistan on Sunday.
The Greek authorities have increased the number of guards at the border with Turkey amid fears there may be a sudden influx of refugees entering Greek territory as the situation in Syria deteriorates.
More than 80% of migrants entering the European Union do so through Greece, which is in the grip of its worst recession in decades.
Some Greek politicians have called for the government to adopt a harder line on illegal immigration.
In the recent election, the far-right Golden Dawn party won enough votes to enter parliament.
Last week the party distributed free food to needy people outside the Greek parliament – but only if they proved they were Greek citizens and submitted important personal information including their blood type, the Greek newspaper Kathimerini reported.
Greece has frequently come under criticism for its handling of immigrants. Amnesty International accused it of treating asylum seekers like criminals and holding them in detention centres.
Greece has frequently called on other European nations to do more to help tackle illegal migration into the EU, arguing that it bears a disproportionate burden.