It is claimed the attack happened while the vehicle was travelling along the Antrim Road on Saturday evening.
Police carried out searches in the area after receiving information about the incident.
A PSNI spokesman said nothing has yet been found.
“Police in north Belfast are warning members of the public in the Antrim Road area to be vigilant and not to touch any suspicious objects but report them to police immediately.”
There has been a heightened alert in north Belfast over recent weeks of a possible dissident republican attack on police.