Police have increased patrols at an east Belfast interface following several nights of increased tension.
Petrol bombs and other objects have been thrown from both sides of a peaceline around the nationalist enclave of Short Strand.
On Tuesday night a petrol bomb was thrown from the Short Strand area into the loyalist Thistle Court area.
Hours earlier a four-year-old girl sustained injuries after a petrol bomb was thrown into the Short Strand as she played in the street.
The girl suffered minor burns in the incident just before 4pm.
The grandfather of one of the girls who was playing ran out into the street and dragged the two children inside, running the injured girl's arm under the cold tap.
Police officers later administered first aid at the scene.
The man said his granddaughter is now too scared to play in his back garden.
CCTV is being examined to see if the person who threw the firebomb can be identified.
Tensions in the area are high after a petrol bomb was thrown from Short Strand into loyalist Cluan Place on Sunday.
A 15-year-old boy was subsequently arrested for arson.
A short time later around 80 people clashed in the area with stones and bottles thrown.
Politicians, community leaders and police have appealed for calm.
Police have increased their patrols in east Belfast as a result of the trouble.
A PSNI spokesman said tensions are high in the area.
"Police would ask parents to ensure that they know the whereabouts of their children, to ensure that they do not get drawn into any violence or anti-social behaviour at interfaces," he said.
The grandfather of one of the girls affected by the petrol bomb thrown into the Short Strand said they could have died.
He said he feared attacks would intensify as the parading season gets under way.
Sinn Fein councillor Niall O Donnghaile said people in the area had already suffered as a result of the flags protests and appealed for calm.
He said: "We all have a responsibility – as do the PSNI – to ensure that we are able to have a peaceful summer for everyone."