The man investigating the killing of former Lebanese Prime Minister Rafik Hariri has traveled to Syria to question officials about the assassination.
Detlev Mehlis was driven from Beirut to the Syrian capital Damascus in a heavily guarded motorcade, according to Lebanon's official National News Agency.
It is not clear who the UN chief prosecutor wants to interview but the Lebanese press has named Syria's last intelligence chief in Lebanon, Rustum Ghazale and Interior Minister Ghazi Kenaan, Syria's intelligence chief for Lebanon until 2000, as possible candidates.
The United Nations has already accused Syria of hampering the investigation by failing to respond to requests to interview officials and hand over documents.
Syria has denied these charges.
Mehlis, a German prosecutor, has named four pro-Syrian Lebanese generals as suspects in the bombing that killed Hariri and 20 other people in central Beirut.
