The grenade was thrown at officers near Pottingers Quay, as they responded to reports of anti-social behaviour.
As they returned to their vehicle, the device was thrown and landed at police officers' feet but failed to explode.
It was the second attack in Belfast with 48 hours targeting police or those with links to the security forces.
Supt Bobby Singleton said "people could have been killed last night".
"The device was thrown and landed very close to officers, basically at their feet, and they had to leave the area," he said.
"There were young people in this area, within feet of where that grenade landed at the feet of the police officers as well.
"It is really only through good fortune that we are not looking at fatalities.
"This was a reckless and senseless attack and what really concerns me is that this is the second time in 48 hours that terrorists have put explosives on the street, in the vicinity in particular of young people who were in the area at this time."
On Thursday, a bomb found was found in Linden Gardens, north Belfast, that police said may have fallen from a car belonging to a man with connections to the armed forces.
Earlier, PSNI Chief Constable George Hamilton described the Short Strand attack as an "act of madness".
Writing on his Twitter account, Mr Hamilton said it "could have killed or injured police or local residents".
A number of homes were evacuated on Friday night while Army bomb officers examined the unexploded grenade.
No damage was caused and none of the police officers was injured.
The security operation in Short Strand ended on Saturday afternoon and the area between the Albertbridge Road and the Bridge End flyover has reopened.
Police said residents and motorists had faced "significant disturbance" as a result of the security operation and apologised.
Police have said a "military-style hand grenade" thrown at a police patrol in Belfast could have killed officers and young children.