Oslo - Norwegian police Friday said some 30 protesters, including several minors, were arrested after counter-protesters attacked a pro-Israel rally.
Police said a dozen people were likely to be charged for assaulting police officers or damaging property on Thursday evening.
At least five police officers were injured in the scuffles or by stones, and police also seized firebombs and knives.
The public rally in support of Israel was held outside parliament, and was attended by several hundred people.
Speakers included Siv Jensen, leader of the opposition, populist Progressive Party.
After the rally, there were scuffles and some counter-protesters also fired fireworks at police, who responded with teargas.