A legal ruling that would send 28 detained immigrant mothers and their children back to Latin America despite their claims they would be persecuted upon return was upheld on Monday by a federal appeals court.

A panel of the US Court of Appeals for the Third Circuit denied asylum to the women from Honduras, Guatemala and Ecuador, saying their fears they would face violence at home were "not credible".

A report by the UN's children's agency earlier this month indicated that people are fleeing some Latin American countries, such as Guatemala and Honduras, due to high crime and poverty, and that deporting vulnerable people back would be tantamount to a "death sentence".

Judge D Brooks Smith wrote in the decision that the justices were "sympathetic to the plight" of the petitioners, but he added that since the women arrived in the US "surreptitiously" they were not entitled to constitutional protections.

The women came over the US border in Texas but are being held at the Berks County Residential Center in Pennsylvania, said American Civil Liberties Union attorney Lee Gelernt, who represented the families.

"The decision is wrong as a matter of history and precedent, and if left intact, will be the first time in the history of the country that noncitizens on US soil cannot obtain federal court review of the legality of their deportation," Gelernt said in a statement.

The families plan to appeal, he said.

Government attorney Joseph Darrow, representing the federal agencies, said he was unable to comment.

An email seeking comment from a Department of Justice spokesman wasn't immediately returned Monday.

Gerald Neuman, a Harvard Law School professor who co-chairs the school's Human Rights Program, said on Monday the ruling is a "shocking outcome".

"This court has held that these people have no rights under the Suspension Clause," he said, referring to a section of the US Constitution which says the right of habeas corpus cannot be suspended unless in cases of rebellion or invasion.

Neuman pointed out that courts have even ruled that prisoners held at Guantanamo Bay have the right to contest their imprisonment.

Neuman and more than a dozen scholars and organizations filed a brief in support of the immigrants' arguments, outlining why they should have the right to contest their detention.

No other court has taken a serious look at whether people who crossed the border and are arrested in the interior of the country have the right to challenge the legality of their being held for removal, Neuman said, adding that he hopes the full court of appeals takes a look at the case.

"This case has significance," he said. "Where is this going to stop?"

The residential center where the women are being held, in Leesport, about 104km northwest of Philadelphia, has been under contract with immigration authorities since 2001.

It is one of three such facilities nationwide. The other two are in Texas.

Source: Agencies