A two-year-long political crisis in Macedonia is entering a dangerous phase, with nationalists accused of stirring up ethnic tensions in a bid to disrupt a corruption probe.

Thousands of ethnic Macedonians have held evening protests against three ethnic Albanian parties forming a coalition government with the Social Democrats. The country's president, Gjorge Ivanov, has sided with the protesters and so far has withheld approving a coalition government that would shut out the main nationalist party.

European Union leaders and analysts say the mounting political confrontation could spin out of control, adding to increasing ethnic tensions across a destabilizing Balkans.

A group called For a United Macedonia announced Monday that it would continue to organize mass rallies in the capital, Skopje, as well as in other towns nationwide against the formation of the coalition. The group accuses the prime minister of neighboring Albania, Edi Rama, of being the true author of the coalition idea.

Farmers on tractors participate in a protest in fr Farmers on tractors participate in a protest in front of the government building in Skopje, Macedonia, March 10, 2017. Thousands of ethnic Macedonians have held evening protests against three ethnic Albanian parties forming a coalition government with the Social Democrats. Farmers on tractors participate in a protest in front of the government building in Skopje, Macedonia, March 10, 2017. Thousands of ethnic Macedonians have held evening protests against three ethnic Albanian parties forming a coalition government with the Social Democrats.

'People won't go home'

"The masks have fallen," Bogdan Ilievski, protest organizer and one of the group's leaders, said in a statement. "We are in favor of a united Macedonia for all, and we are against platforms written in other countries, which some of our politicians won't clearly reject. Despite their attempts to hide their true intentions, they will be met with strong resistance from the democratic public. The people won't go home."

One of the key demands of the ethnic Albanian parties is that the Albanian language be recognized as an official second language. Ivanov has called the demands for greater recognition of ethnic Albanian rights a "threat to Macedonia's sovereignty." A quarter of Macedonia's population is ethnic Albanian.

The standoff between the country's two ethnic groups worsened last December when the Macedonian nationalist party VMRO narrowly won parliamentary elections. The Albanian parties declined to enter a coalition government with VMRO, deciding instead to partner with the Social Democrats.

FILE - Zoran Zaev, leader of the opposition Social Zoran Zaev, leader of the opposition Social Democrats, presents the program of the new Macedonian government, at the party headquarters in the capital, Skopje, March 10, 2017. Zoran Zaev, leader of the opposition Social Democrats, presents the program of the new Macedonian government, at the party headquarters in the capital, Skopje, March 10, 2017.

Social Democrats say Ivanov is stirring the ethnic dispute. They argue he is using it as a distraction to withhold giving a mandate to their leader, Zoran Zaev, because Ivanov and former Prime Minister Nikola Gruevski fear the Social Democrats will open probes into illicit wiretapping and corruption allegations that have dogged the VMRO government since 2015.

2001 agreement

A dispute over ethnic Albanian rights appeared to have been settled more than a decade ago when in 2001 a seven-month-long ethnic Albanian insurgency that left more than 100 dead ended with an agreement providing more rights for the country's ethnic minority. Progress, though, on enacting the agreement has been slow.

"To avoid jail time for his friends, President Ivanov is instead inciting ethnic clashes over a nonissue such as the use of Albanian language in public institutions,'" said Gjovalin Shkurtaj, a member of the National Academy of Science of Albania.

On Monday, Zaev and his proposed Albanian coalition partners started talks on electing a new parliamentary speaker in a bid to persuade Macedonia's president to back down. Zaev is backed by 67 out of 120 lawmakers. VMRO is demanding a new election.

It isn't often a political dispute in a country of just 2 million prompts the alarm of policymakers in Brussels or Washington, but disputes in the Balkans historically have had outsized consequences for Europe — from the 1914 assassination by a Bosnian Serb of Archduke Franz Ferdinand of Austria, the heir presumptive to the Austro-Hungarian throne, which triggered the First World War, to the post-Cold War disintegration of the Yugoslav state that kicked off a decade of internecine warfare drawing in NATO.

Earlier this month, the EU's foreign policy chief, Federica Mogherini, visited the Macedonian capital and urged Ivanov to allow Zaev to form a government.

"I asked the president to reflect on the way forward and to reverse his decision in the interests of all citizens in this country," Mogherini told reporters.

European Union leaders already are scrambling to try to tamp down an ethnic flare-up between Serbia and its former province Kosovo. In January, Serbia's president warned he's ready to send troops to Kosovo to protect Serbian nationals there, if necessary. Serbian President Tomislav Nikolic said the two countries were on the verge of a conflict.

FILE - Gravestones are seen at sunrise at a memori FILE - Gravestones are seen at sunrise at a memorial complex near Srebrenica, 150 kilometers (94 miles) northeast of Sarajevo, Bosnia-Herzegovina, July 11, 2015. Twenty years earlier, Serb troops overran the eastern Bosnian Muslim enclave of Srebrenica and executed 8,000 Muslim men and boys, which International courts have labeled as an act of genocide. FILE - Gravestones are seen at sunrise at a memorial complex near Srebrenica, 150 kilometers (94 miles) northeast of Sarajevo, Bosnia-Herzegovina, July 11, 2015. Twenty years earlier, Serb troops overran the eastern Bosnian Muslim enclave of Srebrenica and executed 8,000 Muslim men and boys, which International courts have labeled as an act of genocide.

Bosnia-Herzegovina, Montenegro

Other issues dividing parties and public opinion include whether to tilt geopolitically to the EU or Russia and border disputes. Ethnic tensions are on the rise also in Bosnia-Herzegovina and Montenegro. Bosnia remains split among Serbs, Bosnians and Croats, and the wounds of their vicious three-year-long war of the 1990s have not yet begun to heal.

The ethnic flare-ups coincide with the Kremlin's bid to expand its influence across an increasingly unstable Balkans, say analysts. From offering help with disaster relief to supplying sophisticated weaponry, including warplanes, Moscow has been on a charm offensive in a region Russia has viewed historically as in its sphere of influence.

In Serbia, Moscow's diplomatic offensive apparently is paying off. A recent Gallup Poll suggested Serbs viewed Russia as a more dependable ally than NATO, an organization Belgrade officially wants to join.

In Macedonia, a Russian hand is also being played. Moscow is accusing the West of trying to install a government in Macedonia that would help Albania pursue expansionist policies. EU leaders say Moscow is determined to stop the Balkans from integrating with NATO.

Zaev has warned that miscalculations in the current deadlock could "set fire to the country."