A group of migrants trying to enter Macedonia from Greece have pelted police with stones, injuring several officers.
Government spokesman Aleksandar Gjorgjev said the situation was calm and stable by midafternoon on November 28.
According to the Macedonian Interior Ministry, 18 policemen were injured in the brief but intense clashes. Two of them were hospitalized in the nearby town of Gevgelija.
The Associated Press news agency reports that the Macedonian police threw stun grenades and fired plastic bullets at the migrants.
Doctors from the Red Cross and other NGOs say they treated 20 migrants for head injuries and breathing problems.
The accidental electrocution at the top of a train carriage of a 24-year-old Moroccan, who suffered severe burns, sparked the unrest among the migrants.
Tensions escalated after the Macedonian Army began putting up a 3-meter-high metal fence on the country's southern border with Greece on November 27.
Gjorgjev said that fence will serve "to direct the inflow of people towards the controlled points for their registration and humane treatment."
Two weeks ago Macedonia, Serbia, and Croatia imposed restrictions on migrants who are not from war zones such as Syria, Afghanistan, and Iraq.
That has led to a chaotic buildup at the Macedonian-Greek border and days of protests by Iranians, Pakistanis, Moroccans, and others.
With reporting by AFP and Reuters