Protest organizers say at least 50,000 people took to the streets of Skopje to protest against a possible coalition government that includes the Social Democrats and ethnic Albanians.
Macedonia's conservative President Gjorge Ivanov has refused to task the leader of the Social Democrats, Zoran Zaev, with forming a government with the ethnic Albanian parties.
Ivanov said he would not support a mandate for anyone backing "a platform undermining Macedonia's sovereignty, territorial integrity and independence," which is an apparent reference to a controversial demand by the ethnic Albanian parties to make Albanian a second official language in the country.
The protests have been in support of the president's resistance to the proposed coalition.
Macedonia has struggled to form a new government after an inconclusive December election. The conservative VMRO-DPMNE secured 51 seats in the 120-seat parliament, two more than the Social Democrats. But the conservatives did not reach a deal to form a coalition with the Albanian parties, which would have secured a majority in parliament.
EU Enlargement Commissioner Johannes Hahn was in Skopje to encourage the president to allow the formation of the coalition government, saying in a tweet that there's no time to lose.
More than one fourth of Macedonia's 2.1 million population is ethnically Albanian and their language is currently only recognized in certain regions.
"The language we all understand is Macedonian and the (minority demand) is only aimed at breaking up the country. That's why we won't allow it to become the policy of any government," said Bogdan Ilievski, a protest organizer.
kbd/gsw (AFP, AP)