The US government is reportedly planning to build tent cities to house thousands of migrant children separated from their families after entering the country.

The Trump administration is considering erecting temporary shelters at military bases to accommodate the growing number of unaccompanied minors detained after crossing the border illegally.

Many entered the country seeking asylum but were torn from parents who are now in prison or facing prosecution under the government’s new “zero-tolerance” policy.

The number of migrant children held in US custody has grown by a fifth since the Trump administration began an aggressive campaign to deter illegal immigration.

More than 11,000 unaccompanied minors are being held in 100 shelters which are nearly full.

The Department of Health and Human Services (HHS) is looking at building a tent city to hold between 1,000 and 5,000 children at the sprawling Fort Bliss army base near El Paso, Texas, reported the political news agency McClatchy.

Air force bases in Abilene and San Angelo are also being assessed as possible sites for shelters, US officials and other sources told the agency.

“HHS will make the determination if any of the three sites assessed are suitable,” a government official said.

State regulators have found hundreds of health violations at existing shelters.

A lack of supervision and medical care were among 150 breaches noted by investigators at 16 shelters run by Southwest Key Programs, a private company contracted by the HSS Office of Refugee Resettlement.

The policy of separating detained immigrant parents from their children has been driven by attorney general Jeff Sessions, who hopes it will dissuade families crossing the border.

“If people don’t want to be separated from their children, they should not bring them with them,” he said in an interview with conservative radio host Hugh Hewitt last week.

“We’ve got to get this message out,” Mr Sessions added. “You’re not given immunity. You will be prosecuted if you… come illegally. And if you bring children, you’ll still be prosecuted.”

Undocumented immigration across the US-Mexico border Show all 14 1 /14 Undocumented immigration across the US-Mexico border Undocumented immigration across the US-Mexico border Immigrant children, many of whom are separated form their parents, are housed in Texas' tent city Reuters Undocumented immigration across the US-Mexico border A two-year-old Honduran asylum seeker cries as her mother is searched and detained near the US-Mexico border Getty Undocumented immigration across the US-Mexico border Undocumented migrants ride on the top of a freight train referred to as the beast, or La Bestia Getty Undocumented immigration across the US-Mexico border A cage inside a US Customs and Border Protection detention facility in Texas Reuters Undocumented immigration across the US-Mexico border US Border Patrol Academy All new agents must complete a months-long training course at the New Mexico facility before assuming their posts at Border Patrol stations, mostly along the US-Mexico border Getty Undocumented immigration across the US-Mexico border US-Mexico border fence A group of young men walk along the Mexican side of the US-Mexico border fence in a remote area of the Sonoran Desert Getty Undocumented immigration across the US-Mexico border US-Mexico border fence in the US Man looks through US-Mexico border fence into the US in Tijuana, Mexico Getty Undocumented immigration across the US-Mexico border US-Mexico border fence US Border Patrol agent Sal De Leon stands near a section of the US-Mexico border fence while stopping on patrol on in La Joya, Texas Getty Undocumented immigration across the US-Mexico border US Border Patrol Academy US Border Patrol instructor yells at trainees after their initial arrival to the academy Getty Undocumented immigration across the US-Mexico border Memorial service in Guatemala Families attend a memorial service for two boys who were kidnapped and killed in San Juan Sacatepequez, Guatemala. Crime drives emigration from Guatemala to the United States, as families seek refuge from the danger Getty Undocumented immigration across the US-Mexico border Arrests on the border Undocumented immigrants comfort each other after being caught by Border Patrol agents near the US-Mexico border Getty Undocumented immigration across the US-Mexico border Detention holding facility A boy from Honduras watches a movie at a detention facility run by the US Border Patrol Getty Undocumented immigration across the US-Mexico border Mexican farm workers Mexican migrant workers harvest organic parsley at Grant Family Farms in Wellington, Colorado Getty Undocumented immigration across the US-Mexico border Mexican family in Arizona A Mexican immigrant family sits in the living room of their rented home in Tuscon, Arizona. The family that Arizona's new tough immigrant law had created a climate of fear in the immigrant community. Getty

The American Civil Liberties Union has described the policy as “inhumane”, cruel and unnecessary. Critics also said the policy was not being properly communicated, meaning migrants who entered the US are unaware their children will be taken from them.

A Honduran father separated from his wife and child killed himself in a Texas jail in May after suffering a breakdown.

Last month reports claimed the government had “lost” nearly 1,500 children who had arrived in the US alone seeking refuge from violence in their native countries. HSS has argued that it is not their responsibility to keep track of children who are placed with sponsors of family in the US.