The SDLP has warned a "sickening surge" in sectarianism must be avoided in Belfast after a Catholic church was vandalised.
The church, which straddles the nationalist Short Strand and loyalist lower Newtownards Road, had paint splattered over a wall and a stained glass window.
The attack on St Matthew's Church last night followed the desecration earlier in the day of a memorial a short distance away from where two Protestants - James McCurrie and Robert Neill - were gunned down by the IRA during disturbances in June 1970.
Both incidents were condemned by police, the Ulster Unionist Party, Sinn Fein and the SDLP.
Mr Leo van Es of the SDLP said the incident was "disgusting and despicable".
"A church is a holy and sacred place and should be treated with the respect and sanctity it deserves.
"Yesterday's attack on the IRA victims' memorial on Newtownards Road was senseless. There can be no excuses for such shallow displays of vandalism and thuggery.
"More importantly, I would also like to appeal for calm. At a time of such political instability, the last thing the people of East Belfast need is another sickening surge of sectarianism."
Inspector David Moore said: "An attack on any place of worship is reprehensible and police would call on anyone within the local community who has information about this incident to come forward."
Former Ulster Unionist Economy Minister Sir Reg Empey was saddened by the latest attack and the desecration of the memorial.
"Two wrongs do not make a right and I would call on communities to remain calm and take guidance from local leaders who are doing an excellent job," the East Belfast MLA said.
Sinn Fein councillor Mr Joe O'Donnell appealed for calm after the attack on St Matthew's but accused some unionist politicians of inflaming tensions.
"There is, I have to say, a good deal of local anger at this attack," he said.
"Some people are linking it to an attack on a memorial close by the previous day.
"In the wake of that attack there was much positive comment from unionist political leaders in the area. I welcomed this and believe that we can work through this situation and get things calmed down.
"However some unionist politicians did choose to use words which could only have had the effect of inflaming passions within their own community.
"I would prefer today to try and work through the various bodies working along this interface and ensure that last night's attack does not create further unwanted and unnecessary violence in this area."