Eight Indian nationals who were detained and sentenced to death in Qatar on reported espionage charges have been released, according to Indian authorities.

“The Government of India welcomes the release of eight Indian nationals working for the Dahra Global company who were detained in Qatar. Seven out of the eight of them have returned to India,” said the Ministry of External Affairs in a statement on Monday.

“We appreciate the decision by the Amir of the State of Qatar to enable the release and home-coming of these nationals.”

The eight nationals were ex-servicemen of the Indian Navy, according to a letter dated to December 2022 by an Indian minister and posted by another parliament member on X, formerly Twitter.

They had been working for Dahra Global Technologies, a defense services provider based in Qatar, according to CNN News18.

Their conviction in Qatar was shrouded in secrecy, and it’s still not clear what offense they committed or what they were charged with. Qatar has not publicly addressed the arrest, sentencing and subsequent release of the eight Indian citizens.

CNN has previously reached out to Qatari authorities for comment.

CNN affiliate CNN-News18 reported at the time that the eight Indians had been detained in August 2022 on spying charges. CNN cannot independently verify the charges.

The Indian ministry has not shared details about the charges either, citing “the confidential and sensitive nature of proceedings of this case.”

The ministry announced last October that it had received information about a Qatar court passing the death penalty for the eight nationals, saying it was in touch with all the men’s families and were taking up the verdict with Qatari authorities.

In December, the ministry said the sentences had been reduced, with a detailed judgement to come. It did not elaborate on what the reduced sentences would be.

After their release on Monday, several of the men thanked the Indian government. “We have waited almost for 18 months to be back in India. We are extremely grateful to (Modi). It certainly wouldn’t have been possible without his personal intervention,” one told Indian news agency ANI on camera.

The case has garnered widespread attention in India and been framed as a test of diplomacy for Prime Minister Narendra Modi’s government.

Jairam Ramesh, a general secretary of India’s main opposition party, demanded last year that the government “explain to the families and the people of India” why it had not yet secured the men’s release more than seven months after their detention. He also highlighted the strong trade relationship between the two countries, saying the Indian diaspora made up a quarter of Qatar’s population.

Hundreds of thousands of Indians provide a large proportion of Qatar’s more than 2 million strong foreign workforce – which accounts for 95% of labor in the gas-rich Gulf state, according to United Nations data.

The release of the eight nationals comes just a few months ahead of the start of the Indian election, with the country heading to the polls in the spring – a mammoth election that is likely to see Modi secure a rare third term in power.

CNN’s Vedika Sud, Akanksha Sharma, Aishwarya S Iyer, and Kathleen Magramo contributed reporting.