The U.N.-backed Lebanon tribunal said on Tuesday the Lebanese authorities have reported back on measures taken so far to search for and arrest four men wanted in the killing of former prime minister Rafik al-Hariri.

No details on the report were released by the tribunal.

The Special Tribunal for Lebanon (STL) issued indictments and arrest warrants in June for four men, who Lebanese officials identified as Hezbollah members.

So far none of the four men accused has been detained. The tribunal released their names, photographs and details last month in the hope of speeding up the arrests.

Hezbollah, both a political movement and guerrilla army, denies any role in the huge explosion in Beirut which killed Hariri, a Sunni Muslim who served several terms as prime minister, and 21 others, in February 2005.

The tribunal said the Lebanese Prosecutor General had submitted his report on Tuesday, adding that Lebanon's obligation "to arrest, detain and transfer the accused continues."