Police are treating the throwing of two viable devices at officers manning Derry's walls in the early hours of Thursday morning as attempted murder.
This is the second bid this week to murder police officers, after Tuesday evening saw shots being fired at staff who were deployed on the city's walls.
The devices were discovered at 3:40 BST and the area was immediately secured.
After examination by ATO, they were made safe and removed - no evacuation or road closures were carried out.
PSNI superintendent Gordon McCalmont said: "This was a reckless act and those responsible have shown a blatant disregard for life.
"Our officers are working hard to keep people safe and there can be no justification whatsoever for this.
Thankfully, no one was injured, however, had these devices exploded we could have been looking at something very different today."
Six shots were fired
This is the second time over the course of this week that police have treated an attack on them throughout the ongoing trouble in the Bogside and Fountain area of Derry as attempted murder.
Dissident republicans were behind a gun attack on police officers, in which an automatic weapon is believed to have been used in the incident on Tuesday night, in which six shots were fired.
Mr McCalmont condemned the attack on the force: "This is the second bid this week to murder police officers in the city. On Tuesday night, shots were fired at police officers deployed on our city's Walls.
"Fortunately on Tuesday night, and early this morning, none of our officers were injured.
"Police officers should not be targeted under any circumstances and their lives should not be put in danger by simply doing their jobs, keeping people safe."
Fifth consecutive night of violence
Midnight Eleventh night bonfire here in the Fountain pic.twitter.com/23fmP8kP3E— Kevin Sharkey (@tv_KevinSharkey) July 11, 2018
In Derry there was a fifth consecutive night of violence, although it was reduced compared to the previous four nights.
Police closed the city walls to the public after petrol bombs were thrown from the Bogside.
Police said 16 petrol bombs in total were thrown at police in the vicinity of the city walls.
Some small fires also disrupted traffic on the nearby Lecky Road.
Petrol bombs also thrown at the police and a fire engine in the Collon Lane area of Carnhill.
In the Fountain estate, the national flags of Ireland and Palestine, as well as a Che Guevara flag were burned on a community bonfire when it was lit at midnight.