A police officer has escaped injury after a patrol car was attacked in Belfast.

Police say the windows of the vehicle were smashed and a petrol bomb was thrown into the car in the Upper Newtownards Road area at around 7.30pm.

Two officers were in the vehicle at the time and police say they were lucky to escape without injury.

The attack has been condemned by Assistant Chief Constable George Hamilton, who said it was being treated as attempted murder.

The incident happened as part of the latest outbreak of sporadic trouble involving loyalist groups in parts east and south Belfast.

Several roads were blocked at one stage, as part of the continuing protests against a decision by Belfast City Council to restrict the flying of the union flag at city hall.

Police were also attacked with petrol bombs and fireworks at Broadway, not far from the M1 motorway.

The patrol car incident took place near the offices of east Belfast MP Naomi Long, a member of the non-sectarian Alliance Party who has been warned her life is under threat.

Last week, Ms Long was told by police to stay away from her home and her office on the Newtownards Road because of fears for her safety.

Constituency offices used by the party were also attacked in Bangor, Co Down, and Carrickfergus, Co Antrim.

There were a number of other protests in regional areas of Northern Ireland, including Limavady, Co Derry, and Ballycastle, Co Antrim, which passed off without any violence.

Northern Ireland First Minster Peter Robinson, leader of the Democratic Unionist Party, and Mike Nesbitt, leader of the Ulster Unionist Party, held talks in Belfast earlier to discuss the trouble on the streets.

Both have been heavily criticised by nationalist representatives over their leadership since councillors in Belfast voted a week ago in favour of only flying the flag on designated days.

They have already called for loyalist restraint, and according to a statement tonight they agreed to work on a "joint basis with a view to urgently bringing forward political proposals to address widespread concerns across the community".

Another meeting is planned for tomorrow.