Published Wednesday, 30 April 2014
It comes after four men threw seven petrol bombs at the Alliance Party constituency offices on the Upper Newtownards Road on Tuesday night. The attack was caught on CCTV.
Police are continuing to investigate who was responsible, but Sinn Féin's Mr McGuinness has said that the UVF is to blame.
He said: "The activities of the UVF in east Belfast over the course of the last two years have been particularly disgraceful - criminality of the worst kind.
I have very carefully monitored the response of unionists over the past 18 months and there has been a deficit of unreserved condemnation of the criminality emanating from the UVF in east Belfast.
Martin McGuinness, Sinn Féin
Mr McGuinness added: "The response of unionist political leaders to the activities of these people has been inadequate and I also think the response of the police has been inadequate."
The attack has been condemned "without reservation" by DUP First Minister Peter Robinson who described it as "senseless", adding: "No cause (was) ever advanced by such criminality."
Meanwhile the UUP leader Mike Nesbitt said that the attack was "deplorable", adding: "It is mindless, pointless, and not in anyone's interests. I really fail to understand what those who carried out the attack thought they were going to achieve or what cause they were furthering."
But Mr McGuinness said more must be done to condemn such incidents.
"We have seen over the past couple of days defenceless visitors to our shores attacked in the most despicable fashion," he said.
"You just have to put yourself into the shoes of someone who was come from eastern Europe and to face attack like this is the worst form of cowardice.
"We need to stand up for these people and we also need to stand up for the Alliance Party in relation to these attacks on their offices."
Police and fire crews were called to the petrol bombing at around 11pm.
These attacks are not just wrong they are utterly futile.
Naomi Long, Alliance
Alliance MP for East Belfast Naomi Long said it's the third time the building has been targeted but said any attempt at intimidation is "futile" as the party will continue to represent local people.
The party deputy leader continued: "I don't want to speculate as to who might be behind this attack but if there's anyone who still believes after all this time that me or my colleagues will be intimidated out of east Belfast I can reassure them that will not happen.
"There is scorch damage and smoke damage to the building and obviously broken windows where they threw masonry at the first floor windows to break them in order to try and get the petrol bombs inside, but the windows didn't break completely and the damage is to the exterior."
Parties from across the political spectrum have condemned the attack.
SDLP leader Alasdair McDonnell said: "This is not the first time the Alliance Party has been targeted and it cannot be tolerated. What happened last night was wrong and can never be justified."
Secretary of State Theresa Villiers said: "Once again we have seen the targeting of the Alliance party offices. These types of attacks are totally unacceptable. I would appeal to anyone with information on those responsible to pass it to the PSNI as soon as possible."
Anyone with more information has been asked to contact the PSNI.
© UTV News