The chief U.N. investigator probing last year's assassination of former Lebanese Prime Minister Rafik Hariri traveled to Syria Tuesday to interview senior government officials.

Lebanese officials say Belgian prosecutor Serge Brammertz is to meet with Syrian Vice-President Farouk al-Sharaa, who was the country's foreign minister at the time of Hariri's assassination.

It was not immediately clear if the investigator will talk to President Bashar al-Assad, who has repeatedly denied any Syrian role in the Killing.

Brammertz took over the investigation in January from Detlev Mehlis, whose report to the United Nations implicated senior Syrian security officials in the killing. The report also said Damascus was impeding the inquiry.

Hariri and 22 other people were killed in a massive truck bombing in Beirut on February 14, 2005.

The murder sparked widespread anti Syrian protests in Beirut and intensified international pressure forcing Damascus to withdraw its troops from Lebanon after 29 years.