Youths hurled petrol bombs at police at a bonfire site in Ballymena, Co Antrim early today.
The trouble began in the Fisherwick area of the town shortly after midnight when a gang gathered around a fire began hurling petrol bombs at passing traffic.
When police arrived two petrol bombs were thrown at them. Fire crews were also attacked with other missiles.
There were no reports of any injuries or damage.
One man was later arrested for disorderly behaviour.
Meanwhile, in Derry police came under attack with petrol bombs following trouble in the Fountain Estate area last night.
Two petrol bombs, a number of paint bombs and other missiles were thrown at police vehicles as a small group of youths built a makeshift barricade and set it alight.
Another two petrol bombs were thrown in the direction of the Fountain Estate.
There were no reports of any injuries or damage.
PA