"Today there will be 13 demonstrations in the Helsinki city area. The number of participants varies from a couple of persons to dozens of people per demonstration. Some impact on traffic is expected," the Helsinki police wrote on their Twitter page.
Trump earlier faced mass protests against him in London during his recent visit to the UK.
The summit will be the first personal talks between the US president and his Russian counterpart, as previously they had only met on the sidelines of international events.