PHNOM PENH--Two Cambodian journalists who worked for U.S. government-funded Radio Free Asia were back on trial Friday on espionage charges that rights groups have characterized as a flagrant attack on press freedom.

One of the journalists, Uon Chhin, said Thursday he still hoped the court would drop the case. "It has been nearly two years now, and I thought this groundless charge would be finished, and I hope the court will drop all the charges against us, so that we can exercise our rights fully to make a living, like other Cambodians," he said.

Uon Chhin and Yeang Sothearin are charged with undermining national security by supplying information to a foreign state, which is punishable by up to 15 years in prison. They were arrested in November 2017 during a crackdown on the media and political opponents of Prime Minister Hun Sen's government during the run-up to the 2018 elections.

The pair testified two weeks ago in Phnom Penh Municipal Court that they had covered news events for RFA after leaving its employment, but they denied any wrongdoing.

Radio Free Asia closed its Phnom Penh bureau in September 2017, citing "unprecedented" government intimidation of the media. By the end of 2017, Cambodia's government had closed more than two dozen local radio stations, some of which had rebroadcast RFA's programs. The English-language newspaper The Cambodia Daily also was forced to close, muting almost all critical media inside the country.

RFA is funded by an independent U.S. government agency and says its mission is "to provide accurate and timely news and information to Asian countries whose governments prohibit access to a free press." Its programs are aired by radio and television and carried online.

Police initially said the two had been detained for running an unlicensed karaoke studio. But they were later accused of setting up a studio for RFA, which they deny, and were charged with espionage. Their release on bail has been conditional on monthly police station visits and confiscation of their passports, which they say makes it difficult to find jobs.

Uon Chhin testified earlier that his contract with RFA had ended and he was building a karaoke studio when he was arrested, but denied allegations that it was meant for the secret use of his former employer. He said he sent video clips at the request of his former boss, and they concerned openly available news, not state secrets.

Yeang Sothearin also acknowledged working on two stories after leaving RFA's employ. He said he didn't realize it would get him in legal trouble, because it was simply news already known to the public.

The judge expressed skepticism at their explanation, questioning why he would send information when Radio Free Asia had already shut down its office in Cambodia.

Human rights and press freedom groups have urged that the charges be dropped.

"As long as Cambodia treats journalists like criminals, its reputation as a failed democracy will remain," Shawn Crispin, senior Southeast Asia representative for the New York-based Committee to Protect Journalists, said ahead of the last trial session.