Image copyright AP Image caption Perry said Texans had paid "too high a price" for the federal government's "failure" to secure the border

The governor of Texas has ordered 1,000 National Guard troops to the US border with Mexico to protect against what he described as criminals, human traffickers and drug cartels.

Rick Perry, a Republican, said he had to act because the federal government had failed to secure the border.

Mr Perry 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, Mr 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.

"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 Mr 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 $12m (£7m) per month.

'Militarising the border'

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, Mr Obama has asked Congress for $3.7bn 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 Mr 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 militarising 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."