Local residents on Chios, angered by government's determination to go ahead with the creation of closed migrant centers on the islands, on Wednesday barged into a hotel near the construction site and attacked eight police officers who are staying there.
According to Greek police, the officers were injured, while there are concerns that protesters may have also removed equipment.
The officers are part of several units sent to the islands of the eastern Aegean to prevent locals from stopping construction in the selected sites.
On Lesvos, officers fired tear gas to disperse hundreds of people attempting to approach a site earmarked for a new migrant centre, in what is the second day of protests.
Two officers and two residents are believed to have been injured.