Four police officers were injured during overnight violence in Derry, the RUC said today.
Police came under attack from masked petrol bombers in the Gobnascale area.
Around 20 petrol bombs were thrown and two vehicles hijacked and set on fire.
Trouble started when a number of masked men hijacked a bus in Trench Road in the city and set it on fire a short distance away in Irish Street.
Police officers who moved in and put out the fire came under petrol bomb attack.
Another vehicle was hijacked in the same area and later found burned out.
Meanwhile north Belfast Democratic Unionist Party MP Nigel Dodds was having talks with senior RUC officers today after renewed attacks on homes on the Protestant side of the peaceline.
Last night a petrol bomb caused scorch damage to a house in the Shankill Road area.
Local residents claimed two other devices were thrown over the peaceline wall but failed to explode.