LONDON/GENEVA (Reuters) - Britain’s foreign minister and United Nations human rights rapporteurs separately called on Thursday for the release of two Reuters reporters detained in Myanmar, after a judge rejected a request for their case to be dismissed.

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Foreign Secretary Boris Johnson said on Twitter that Myanmar must show its “commitment to media freedom” while the U.N. special rapporteurs said in a joint statement that the pursuit of the case against Wa Lone, 32, and Kyaw Soe Oo, 28, gave rise to “grave concern for investigative journalism”.

A Myanmar government spokesman could not immediately be reached for comment.

A court in Yangon has been holding preliminary hearings since January to decide whether the journalists will be charged for possessing secret government papers under the colonial-era Official Secrets Act, which carries a maximum penalty of 14 years in prison.

Judge Ye Lwin rejected on Wednesday a defence request to dismiss the case against the two reporters, who have been held since December, for lack of evidence. The judge said he wanted to hear the eight remaining prosecution witnesses out of the 25 listed, according to defence lawyer Khin Maung Zaw.

On Tuesday, seven Myanmar soldiers were sentenced to 10 years “with hard labor in a remote area” for participating in a massacre of 10 Rohingya Muslim men in northwestern Rakhine state last September, the army said.

Yanghee Lee, U.N. special rapporteur on Myanmar, and David Kaye, U.N. special rapporteur on the right to freedom of opinion and expression, noted the journalists could be sentenced to longer terms if found guilty.

“The perpetrators of a massacre that was, in part, the subject of Wa Lone and Kyaw Soe Oo’s reporting have been sentenced to 10 years imprisonment. And yet these two reporters face a possible 14 years imprisonment. The absurdity of this trial and the wrongfulness of their detention and prosecution are clear,” they said in a joint statement.

Special rapporteurs are independent experts appointed by the U.N..

The country’s ambassador to the U.N., Hau Do Suan, said last month that the journalists were not arrested for reporting a story, but were accused of “illegally possessing confidential government documents”.

ARMY CRACKDOWN

An army crackdown, unleashed in response to Rohingya militant attacks on security forces in August, has been beset by allegations of murder, rape, arson and looting. The U.N. and United States described it as ethnic cleansing - an accusation which Myanmar denies.

Nearly 700,000 Muslim Rohingya have fled Rakhine state and crossed into southern Bangladesh since then.

After the U.N. experts made their comments, Johnson took to Twitter on the case. “Very disappointed to hear Burmese @Reuters journalists Kyaw Soe Oo and Wa Lone are now to face trial,” he said. “Reiterate my calls for their release: Burmese authorities must show their commitment to media freedom.”

At this stage the prosecutor is trying to persuade the court to file charges. The preliminary proceedings are still underway and only after they are completed is the court expected to decide whether to send the two reporters to trial.