Chief UN investigator Serge Brammertz, who is probing Lebanese ex-Premier Rafik Hariri's assassination, traveled to Syria Wednesday morning and returned to Lebanon in the afternoon, local Naharnet news website reported.

Brammertz, along with a team of investigators, made the round trip overland through the Masnaa border checkpoint in east Lebanon' s Bekaa Valley, the terse report said without disclosing further details.

Rafik Hariri was killed along with 22 others in a massive bomb blast in Beirut in February 2005. A UN probe has implicated Syrian officials in the killing though Damascus has denied its role.

Brammertz, a Belgian criminologist, will submit his updated report to the UN security council on July 19.

Hariri's death sparked massive protests in Lebanon. Under mounting international pressure, Syria withdrew its forces from Lebanon in April 2005, ending a decades-long military presence there.