A suspected grenade was thrown at a police Land Rover overnight at Milltown Row in west Belfast.
Officers were on patrol, just off the Falls Road, when the vehicle was hit by an object, causing a loud bang.
No officers were injured and the car was not badly damaged.
Police in west Belfast are currently at the scene of the overnight attack.
The remnants of the suspected grenade have been recovered and taken away for forensic testing.
Chief Superintendent Jonathan Roberts said officers were in the Falls Road area conducting routine patrols when the incident happened shortly after 2am.
A loud bang was then heard and the police Land Rover made its way to a place of safety.
“A police operation was immediately implemented to ensure the safety of everyone in the area and that operation is ongoing at present. Further searches are being conducted this morning to ensure there are no other devices present which could endanger members of the public,” said Chief Superintendent Jonathan Roberts.
Chief Superintendent Roberts continued: “This was undoubtedly an attempt to kill or injure police officers who were out on duty in the early hours of the morning working to keep the public safe. This despicable act must be condemned by all.”
He said a full and thorough investigation is underway.
“I would appeal to anyone who noticed any recent suspicious activity in the area or who has any information which could assist us with our enquiries to contact detectives at Musgrave on 101 quoting reference number 79 04/12/19. Alternatively, information can also be provided to the independent charity Crimestoppers on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime,” he added.