WASHINGTON -- US President Barack Obama said on Monday that he welcomes the first indictment relating to the assassination of former Lebanese Prime Minister Rafiq Hariri and the Special Tribunal for Lebanon must be allowed to continue its work.

"This action represents an important step toward ending the era of impunity for murder in Lebanon and achieving justice for the Lebanese people," Obama said in a statement. "I know that this is a significant and emotional time for the Lebanese people, and we join the international community in calling on all Lebanese leaders and factions to preserve calm and exercise restraint."

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"The United States is a strong friend of Lebanon and we stand steadfastly with others in support of Lebanese sovereignty, independence, and stability," he added.

The Lebanese coalition government headed by Saad Hariri, Rafik Hariri's son, collapsed last Wednesday after ministers allied with Hezbollah quit over the expected indictment of members of the Shiite militant group.

But the contents of the indictment filed by the Office of the Prosecutor for the tribunal on Monday were not revealed. The UN-backed tribunal was established to probe the death of Rafiq Hariri and 22 others in a truck bombing in Beirut in 2005, which has been rejected by Hezbollah as a conspiracy by Israel and the United States.

"The Special Tribunal for Lebanon must be allowed to continue its work, free from interference and coercion," Obama said. "That is the way to advance the search for the truth, the cause of justice and the future of Lebanon.

He warned that any attempt to fuel tensions and instability, in Lebanon or in the region, will only "undermine the very freedom and aspirations that the Lebanese people seek and that so many nations support."