The protest began Wednesday daytime and reportedly accumulated some three thousand people.
The protest entered its second day, with no violence having been reported on Tuesday.
After breaking through a police cordon, the crowds moved towards parliamentary buildings, burning pictures of Macedonian President Gjorge Ivanov on their way.
In central Skopje, in the vicinity of the president’s office, violence reportedly continued, with protesters throwing flares and eggs at the premises.
Tensions escalated after a group of people tried to enter the office, Balkan Insight reported. A number of people have been injured, with medics providing assistance to those at the scene.
A journalist is reportedly among the injured.
Twelve people have reportedly been detained, police said.
The situation in the Balkan nation has been tense since March, after Macedonia’s constitutional court allowed the president to pardon politicians accused of electoral fraud. Thousands have taken to the streets of Skopje following the decision. Riot police had to barricade the streets leading to the court building to prevent clashes between government supporters and protesters.