A device exploded near a police patrol in Strabane, Co Tyrone on Tuesday night, the Police Service of Northern Ireland said.
The murder bid happened on the same day Northern Ireland’s former deputy first minister and ex-IRA commander Martin McGuinness died aged 66.
Superintendent Gordon McCalmont said it was “incredibly lucky” no one was killed.
He added: “At this time our assessment is that a device exploded while police were on patrol in the area of Townsend Street shortly after 8.30pm.
“The investigation is at an early stage and we have had to ask some residents to leave their homes while we carry out our inquiries.
“While we are unable to go into specifics of the incident at this stage, I am confident in saying that we are incredibly lucky that the lives of officers and other members of the community were not lost last night.
“We appreciate the understanding and patience of local residents while we carry out our inquiries and would appeal for anyone with information about suspicious activity in the area to contact us.”