The paint bombing of a mural, commemorating the WW1 Battle of the Somme, is being treated as a 'hate crime'.
It follows the burning of a Soldier F banner in Lurgan recently and the paint bombing of republican murals in the north Lurgan area.
Splurges of white paint were discovered on the Avenue Road mural this morning.
A PSNI spokesperson said: "At around 11.20am this morning police received a report that paint had been thrown over a Somme commemoration mural in the Avenue Road area of Lurgan.
"It's believed the damage was caused overnight."
Chief Inspector O'Connor said: "This incident is perceived as a hate crime and I am appealing for anyone with information to please get in touch with police by calling 101, quoting reference 902 10/06/19."
A statement from the Avenue Road Somme Society said: "Once again the ignorant and uneducated fools have attacked a memorial to our Brave.
"This mural is historical and educational and great words spoken by both sides of the community is something that we hold highly.
"Paint washes off and we will continue to educate our town of the True Heroes Of Ulster.
"Anyone any information on this attack please don't be afraid to pass it on to the correct people."
Upper Bann DUP MLA Carla Lockhart said: "This is undoubtedly an attempt to heighten tensions ahead of the marching season.
"We have seen this with the removal of the banner in the town centre already and I would ask for calm heads and not to get drawn into a tit for tat campaign.
"Someone may end up getting seriously injured and this needs to stop now. The paint will be removed and those who died in the battle of the Somme will continue to be remembered.
"It is especially disgusting in the run up to the commemoration of those who so bravely gave their lives at the Somme, British and Irish. We will continue to remember their sacrifice."