A high-ranking Hezbollah militant linked to the 1983 truck bombings at the U.S. and French embassies in Kuwait was among four people indicted by an international tribunal in the assassination of Lebanon's former prime minister Rafik Hariri.

The implication of Hezbollah, the dominant player in Lebanon's new government, threatens to plunge this Arab nation on Israel's northern border into a new and violent crisis. The Shia militant group denies any role in the killing and vows never to turn over any of its members.

The case has further polarized Lebanon's rival factions — Hezbollah with its patrons in Syria and Iran on one side, and a Western-backed bloc led by Hariri's son, Saad, on the other.

The suicide truck bomb that killed Rafik Hariri and 22 others on Feb. 14, 2005, was one of the most dramatic political assassinations in the Middle East.

A billionaire businessman, Hariri was Lebanon's most prominent politician after the 15-year civil war ended in 1990.

In the six years since his death, the investigation has sharpened some of Lebanon's most intractable issues: the role of Hezbollah, the country's most powerful political and military force, and the country's dark history of sectarian divisions and violence.

Rafik Hariri was one of Lebanon's most powerful Sunni leaders; Hezbollah is a Shia group.

The UN-backed tribunal issued the indictments on Thursday without releasing the names of the accused. But a Lebanese judicial official who saw the warrants gave the names to The Associated Press, requesting anonymity because of the sensitivity of the matter. The details of the murder — including how and why it was carried out — are still under wraps.

One of the people named is Mustafa Badreddine, believed to have been Hezbollah's deputy military commander. He is the brother-in-law of the late Hezbollah military commander Imad Mughniyeh and is suspected of involvement in the 1983 bombings of the U.S. and French embassies in Kuwait that killed five people.

The other suspects are: Salim Ayyash, also known as Abu Salim; Assad Sabra; and Hassan Anise, who changed his name to Hassan Issa.

No comment yet from Hezbollah

Hezbollah had no immediate comment Thursday. The group's leader, Sheik Hassan Nasrallah, has denounced the court as a conspiracy by the U.S. and Israel and said last year that the group "will cut off the hand" of anyone who tries to arrest its members. It was a potent threat, given that Nasrallah commands an arsenal that far outweighs that of the national army.

Lebanese authorities have 30 days to serve the indictments on suspects or execute the arrest warrants. If they fail, the court can then order the indictment published. The Hague-based Hariri tribunal can hold trials in absentia if suspects cannot be arrested.

Hariri's son, opposition leader Saad Hariri, hailed the indictment as a historic moment and urged Lebanon's new government to honour the arrest warrants.

"Lebanon has paid the price of this moment, in decades of killings and assassinations without accountability," he said in a statement. "The end of the killers' era has begun, and the beginning of the justice era is approaching."

The indictment raises concerns of a possible resurgence of violence that has bedeviled this tiny Arab country of four million people for years, including a devastating 1975-90 civil war and sectarian battles between Sunnis and Shias in 2008.

Conflicts over the court triggered a political crisis in January that brought down the Western-backed government of Saad Hariri, who had been prime minister since 2009.

He had refused Hezbollah's demands to renounce the court investigating his father's death, prompting 11 Hezbollah ministers and their allies to resign from his unity government. After Rafik Hariri was assassinated, suspicion immediately fell on Syria, since Hariri had been seeking to weaken its domination of the country.

Syria has denied any role in the assassination, but the killing galvanized opposition to Damascus and led to huge street demonstrations that helped end Syria's 29-year military presence.

The tribunal, which is jointly funded by UN-member states and Lebanon, filed a draft indictment in January but the contents were not revealed while Belgian judge Daniel Fransen decided whether there was enough evidence for a trial. The draft has been amended twice since then.

Lebanon formed a new government last month — after five months of political wrangling — that gives Hezbollah unprecedented political clout. But Prime Minister Najib Mikati, who was Hezbollah's pick for the post, has insisted he will not do one side's bidding.

On Thursday, Mikati tried to calm tensions while also navigating between the rival political factions.

"Lebanon's interests should be above all things," Mikati told a news conference, adding that there was no final word yet on who killed Rafik Hariri.

"The indictments are not verdicts," Mikati said.

Saad Hariri has refused to take part in the government and now leads the opposition. Abraham Bryan, an expert on Hezbollah affairs who writes for the leading An-Nahar newspaper, said the indictments were unlikely to have any immediate effect — in part because Badreddine is the only well-known suspect named in the indictment.

"Hezbollah surrounds its military leadership with secrecy," he said. "Nobody knows the three others.… Are they alive or not? Are these their real names or no?"