The United States Consulate in Melbourne and the offices of several members of parliament have been targeted in acts of vandalism.
Victoria police say red paint was thrown at the offices from 4am on Friday and have vowed to "thoroughly" investigate the incidents.
The building housing the United States Consulate General on St Kilda Road in Melbourne was covered in red paint and several foyer windows were smashed.
Graffiti outside the building included the phrases "Free Gaza" and "glory to the martyrs".
Police are also investigating vandalism at offices on Main Street at Mordialloc, Hall Street in Moonee Ponds and High Street, Northcote.