WASHINGTON (AFP) - US prosecutors are dropping charges against two immigrant students accused of raping a classmate, a case that made national headlines after the White House brandished it as proof that an immigration crackdown was needed.

Prosecutors in the state of Maryland near the nation's capital said on Friday (May 5) they would not pursue rape and sex offence charges against Jose Montano, a 17-year-old from El Salvador, and Henry Sanchez Milian, 18, from Guatemala.

Police had accused the male students of raping a 14-year-old girl in a bathroom during school hours.

The allegations from the March incident became a lightning rod in the already intense US debate on immigration.

It took on national dimensions when White House spokesman Sean Spicer said "tragedies like this" were the reason US President Donald Trump "has made illegal immigration and crackdown such a big deal."

But, "the facts of this case do not support the charges originally filed," John McCarthy, the state's attorney for the pro-Democratic Montgomery County just outside Washington, told journalists.

Consequently, his office would not prosecute on first-degree rape and sexual offence charges.

Prosecutors, however, have filed a child pornography charge against Sanchez Milian in connection with images found on cellphones during the investigation, McCarthy said.

'EGREGIOUS' NEW CHARGE

Montano's case has been transferred to juvenile court, McCarthy said, declining to specify charges against him.

A defence lawyer for the teenager told US media he would face charges of distributing and possessing child pornography, which she dubbed "egregious."

In Friday's White House press briefing, Sarah Huckabee Sanders, a deputy White House spokeswoman, said she would not retract Spicer's comments "without further information."

Spicer "was speaking about what he knew at the time," she said.

Asked if White House rhetoric might cause people to jump to conclusions regarding immigrant policy, Sanders replied "not at all," adding that Trump is "a law-and-order president."

Sanchez Milian had been living in the United States without legal documentation according to US media. Now, he will eventually appear before an immigration judge who will determine whether he should be deported.

Days after the case took on national prominence, Sanchez Milian's father was arrested by Immigration and Customs Enforcement officers, according to the New York Times, after it was determined he had entered the US illegally.

Authorities have not discussed details of Montano's immigration status as he is a minor.

An estimated 11 million undocumented migrants live in the United States, most of them Mexicans and other Latinos.