Syria has imposed a travel ban on six officials wanted for questioning by the United Nations commission investigating the assassination of former Lebanese Prime Minister Rafik Hariri.

A committee spokesman did not name the officials, but said they are already being questioned.  Arab media earlier identified one of them as President Bashar al-Assad's brother-in-law, who heads military intelligence.

Damascus recently established its own committee to investigate Mr. Hariri's killing, after a U.N. report linked top Syrian intelligence officials to his February assassination.

Last week, U.N. investigator Detlev Mehlis requested Damascus send the same six officials to Beirut for questioning.  The Syrian panel's move effectively prevents their compliance.

The Syrian state news agency reported earlier today that Syria had invited Mr. Mehlis to Damascus to discuss cooperation with the investigation.

Some information for this story provided by AP and Reuters.