WASHINGTON, Dec. 4 -- The U.S. is very concerned by violence in Lebanon and sees the killing of a Hezbollah commander as an example of negative impact from the Syria conflict, a spokesperson said on Wednesday.

"We've been very concerned by recurring instances of sectarian and political violence in Lebanon," State Department spokesperson Marie Harf said at a press conference.

Hezbollah official Hajj Hassan Hollo al-Laqqis was assassinated overnight Wednesday near his residence in the Lebanese capital of Beirut's southern suburbs, according to a statement issued by Hezbollah, which accused Israel of carrying out the assassination.

"We've talked about the negative impacts that Syria has had in Lebanon and Iraq and elsewhere in the region...and the spill-over violence that we've tragically seen," Harf said.

The U.S. called on all parties to cooperate with a full investigation into the incident, the spokesperson said.