Ireland's top diplomat in a visit to Lebanon on Monday expressed his concern over the slow progress in criminal proceedings against several Lebanese men charged with the killing of an Irish peacekeeper in 2022 in the tiny Mediterranean country.

Micheál Martin, Irish foreign and defense minister, said he was "very, very concerned" about the case. He met with Irish peacekeepers in south Lebanon and with Lebanese Foreign Minister Abdallah Bou Habib and a representative of the Lebanese defense ministry.

Lebanon's military tribunal last June charged four men with the killing of Pvt. Seán Rooney, 24, of Newtown Cunningham, Ireland, following a half-year probe. Rooney was killed on Dec. 14, 2022.

Only one of the suspects, Mohammed Ayyad, was arrested. However, he was released on bail in November, with officials citing his medical condition. The four others facing charges — Ali Khalifeh, Ali Salman, Hussein Salman, and Mustafa Salman — remain at large.

All five are allegedly linked with the Lebanese militant group Hezbollah. Hezbollah has repeatedly denied any role in the killing.

On the fatal night, Rooney and several other Irish soldiers from UNIFIL were on their way from their base in southern Lebanon to the Beirut airport. Two U.N. vehicles apparently took a detour through Al-Aqbiya, which is not part of the area under the peacekeepers' mandate.

Initial reports said angry residents confronted the peacekeepers, but the indictment concluded that the shooting was a targeted attack. The U.N. peacekeeper vehicle reportedly took a wrong turn and was surrounded by vehicles and armed men as they tried to make their way back to the main road.

"We want justice to be done" and for the killers to be "brought to justice," Martin told reporters. "We understand the separation of powers. But we are concerned at the slow pace of the trial. And the Irish people want justice"

UNIFIL was created to oversee the withdrawal of Israeli troops from southern Lebanon after Israel's 1978 invasion, and its mission was expanded following the 2006 war between Israel and Hezbollah.

Relative calm prevailed in the border region after that war until the beginning of Israel's war against Hamas, a Hezbollah ally, in Gaza in October. For more than seven months, Hezbollah and allied groups have clashed near-daily with Israeli forces, with no apparent immediate prospects for a halt to hostilities.