Iran has agreed to free a Lebanese man with permanent U.S. residency who has been imprisoned since 2015, Lebanon’s foreign ministry said Tuesday.

After a request from Lebanese President Michel Aoun and other officials, Iran’s ambassador to Beirut has “expressed the readiness of the authorities in Iran to receive any Lebanese delegation at any time for the extradition of Lebanese prisoner” Nizar Zakka, Lebanon’s foreign ministry said in a statement.

“The Ministry of Foreign Affairs and Emigrants thank the Iranian authorities concerned for ending this file and moving forward the bilateral relations between the two countries,” the ministry added.

Some Iranian media outlets also reported Zakka could be freed soon but did not provide more details.

Zakka, 52, a Lebanese-born U.S. permanent resident and IT expert who lived in Washington D.C., was arrested in Tehran in September 2015 after being invited by the Iranian government to attend a conference on women and sustainable development.

This March 2013 handout image provided by the Friends of Nizar Zakka, shows NizarZakka, a Lebanese technology expert and advocate for Internet freedom, delivering a speech during the MENA ICT Forum conference in Jordan. Courtesy of Friends of Nizar Zakka group via AP

In August 2017, an Iranian court upheld a 10-year prison sentence and $4.2 million fine against Zakka for unspecified espionage charges. His family and human rights groups have dismissed the charges as baseless.

“We have seen news reports about this case,” said a State Department spokesperson, who was not authorized to speak on the record. “This is a matter between Lebanon and Iran. We welcome the release of any unjustly held foreign detainees in Iran. It would be a good day for the Zakka family if Mr. Zakka is allowed to return home to Lebanon.”

Iran’s U.N. mission did not respond to a request for comment.

One of Zakka’s three children, Nadim Zakka, said he had not been informed of any progress in his father’s case. “I really have no idea about the recent developments. Maybe in the next couple of days I’ll know more,” Nadim Zakka, who is based in Houston, told NBC News.

Nizar Zakka’s official twitter account expressed “sincere gratitude” to Lebanon’s president and foreign minister and suggested he would be released soon. “We highly value the support Nizar Zakka has received, and he is looking forward to addressing the public very soon in Beirut,” it said.

Jason Poblete, a Washington-based lawyer assisting the family, referred to Lebanon’s statement, tweeting that “after almost four years, Mr. Zakka looks forward to someday, hopefully soon, rejoining his family & friends.”

And he added: “This reunion would be sweeter if it coincides with #Eid.”

The U.S. has demanded Iran release Zakka along with other U.S. and foreign nationals, accusing Tehran of treating foreign citizens as “hostages” for use as bargaining chips with other governments.

Lebanon’s statement followed a flurry of meetings and contacts in recent weeks between the U.S. and countries that often act as interlocutors with Iran, including Switzerland and Oman. The discussions, along with some public statements by Tehran and President Donald Trump, have prompted speculation that the two countries could be exploring possible direct talks or the release of nationals held in Iran.

The Swiss handle U.S. interests in Iran, as Washington and Tehran have no diplomatic relations.

During a visit to the Swiss city of Bellinzona on Sunday, Pompeo said he was “deeply appreciative” for the country’s assistance in handling the cases of U.S. nationals held in Iran.

“You perform important consular services for our citizens there, and you manage the cases of our missing or imprisoned U.S. citizens, visiting them in Iranian jails and assuring them and their families that their country is doing everything that it can to bring them home,” Pompeo said.

If Iran goes ahead with the release of Zakka, it could represent a tentative move toward defusing soaring tensions between the U.S. and Iran, former officials and experts said. But by freeing Zakka, Tehran would still stop short of releasing a U.S. citizen, which Tehran would likely see as a concession that would need to be met with reciprocal moves by Washington, the former officials said.

At least 12 dual and foreign nationals, or Iranian citizens with foreign residencies, are imprisoned in Iran as of this month, according to the Center for Human Rights in Iran.

Those imprisoned include Siamak Namazi, an Iranian-American businessman, and his elderly father Baquer Namazi, a former UNICEF official, Xiyue Wang, an American graduate student from Princeton University, Morad Tahbaz, who has U.S., British and Iranian citizenship and was detained along with other environmental activists, and Michael White, a U.S. Navy veteran.