“We will pray for peace and seek peace, but there will be no surrender and Serbia will win,” President Aleksandar Vucic of Serbia said on Sunday at a news conference. “If they dare to persecute and mistreat and kill Serbs, Serbia will win,” he continued, adding later, “We’ve never been in a more difficult, complicated situation than today.”

Mr. Vucic, who convened a high-level meeting of security and military officials on Sunday night, said that the Kosovar government was trying to cast him in the same light as President Vladimir V. Putin by blaming the unrest on Serbia’s close relationship with Russia, a fellow Slavic and Orthodox Christian nation.

Kosovo’s leader, Mr. Vucic said during Sunday’s news conference, was trying to take advantage of the global mood by projecting that “big Putin gave orders to little Putin, so the new Zelensky, in the form of Albin Kurti, will be a savior and fight against the great Serbian hegemony.”

Vladimir Djukanovic, a Serbian member of Parliament from Mr. Vucic’s ruling party, also linked the border spat to the war in Ukraine, tweeting, “Seems to me that Serbia will be forced to begin the denazification of the Balkans,” an ominous reference to Russia’s justification for the invasion of Ukraine.

Serbia, a candidate to join the European Union, has maintained close ties with Moscow and has not joined Western sanctions on Russia, though it did vote in favor of a United Nations resolution condemning the Russian invasion of Ukraine. Belgrade and Moscow share animosity for the NATO military alliance because of its bombing of Yugoslavia in 1999, when Mr. Vucic was a spokesman for the Serbian strongman Slobodan Milosevic.

NATO still maintains a peacekeeping presence in Kosovo, with a force of approximately 3,700 troops. In a news release, NATO said its force on the ground was “ready to intervene if stability is jeopardized.”