PRISTINA -- Graffiti appealing to Serb identity to inspire resistance to Kosovo authorities has appeared in the divided city of Mitrovica and other municipalities, as ethnic and diplomatic tensions surround an ongoing vehicle-registration dispute that enters a risky new phase in the Balkans.
The stenciled Cyrillic messages in Serbian and in the red-white-blue of the Serbian flag appeared on walls and public spaces on November 13 in North Mitrovica, a mostly Serb municipality separated from the heavily ethnically Albanian municipality of Mitrovica by the Ibar River.
The targets included a utility box next to a downtown statue of medieval ruler Lazar Hrebeljanovic.
The messages purport to be from a group called Brigade North and say that "from November 21, it's everyone's duty to resist every step of the way."
That's the date that Kosovar authorities plan to start fining local motorists up to 150 euros ($156) for Serbian license plates, which in many cases date back to the 1990s when Kosovo was a province within Serbia.
Ethnic Serbs concentrated in northern Kosovo have blocked roads and staged other protests over the past year in connection with the license-plate dispute and another document standoff, rekindling fears of the kind of sporadic ethnic violence that killed dozens of people in March 2004.
Similar graffitied messages appeared in other towns in northern Kosovo, too, including Zvecan and Zubin Potok.
Kosovar Prime Minister Albin Kurti has long threatened to start converting "SRB" license plates issued to Kosovar Serbs by Serbian authorities before 1999 to "RKS" plates.
There are an estimated 10,000 or so cars whose Serbian plates run afoul of the decree that was issued last month to kick the conversion into motion.
The European Union and the United States have entreated Pristina to delay the move, which has already raised tensions and troop readiness at the 380-kilometer border between Serbia and partially recognized Kosovo, where NATO maintains a decades-old peace-support operation.
But Kosovar authorities began the first phase of their plan on November 1, prescribing warnings for motorists with aging Serbian plates.
Ethnic Serb lawmakers, judges, and police in northern Kosovo recently quit en masse after a Serb police officer was punished for refusing to enforce the new regime.
Then the Belgrade-backed Serbian List party, which has long dominated elections among Kosovar Serbs, vowed to boycott special elections to replace the mayors who quit in protest in four mostly Serb municipalities in northern Kosovo.
Beginning next week, the Kosovar government plan gradually toughens penalties for the Serbian license plates until April 21, when the government decree issued last month says they can start to impound vehicles that are not in compliance.
A handful of countries that border Serbia since the breakup of the former Yugoslavia have significant minority Serb populations with whom Belgrade routinely coordinates and sometimes organizes, including Kosovo, Bosnia-Herzegovina, Montenegro, and North Macedonia.
Belgrade and many ethnic Serbs in Kosovo explicitly reject Pristina's declaration of independence in 2008 and Kosovar institutions.
Serbia has deployed armored vehicles and buzzed the border area with military aircraft in recent months, and NATO's KFOR mission has increased its patrols and flew helicopters on the Kosovar side in September.
In phone calls with Serbian President Aleksandar Vucic and Kurti this month, NATO Secretary-General Jens Stoltenberg urged both sides to avoid actions "that can trigger escalation."
Vucic repeated afterward that Pristina was "brutally violating" the Brussels agreement that both sides signed in 2013 as a first step toward normalizing mutual relations, although that process has mostly stalled.
Kurti, an Albanian nationalist who rose to power vowing to impose "reciprocity" with Serbia, which requires motorists with Kosovar plates to buy temporary ones, argues that Belgrade has imposed a similar obligation for years.
"I once again invite all Serb citizens of our country to not abandon institutions, not to resign, not to leave their jobs, because there would be less service for the people," Kurti said on November 6.
'NATO Go Home'
Kosovar police in North Mitrovica -- decimated by this month's mass resignation -- say they have no idea who is behind this week's graffiti.
It varied slightly from stenciled messages that appeared there three months ago warning, "Don't worry! We're here! We're waiting for you!" The earlier graffiti included "NATO go home!" in English and in Serbian and was signed, not by Brigade North, but by the Northern Brigade. It is unclear what type of groups the "brigades" are, or if they even exist at all.
Those messages of protest preceded a meeting in August between Vucic and Kurti as EU officials pressed them to reinvigorate the normalization process.
EU officials mediated a compromise in August to allow free travel between Kosovo and Serbia for each other's nationals with only ID cards, to sidestep the persistent recognition-related dispute.
EU foreign policy chief Josep Borrell warned in Brussels on November 14 that "We cannot reach this date without having an agreement or we will be on the edge of a dangerous situation."
Later, a reliable source in Brussels told RFE/RL's Balkan Service that Vucic and Kurti would meet late on November 20 or early on November 21 after EU officials invited them to an urgent meeting to resolve the dispute.
The U.S. State Department last month urged Pristina to "extend the implementation period" for the new license-plate regime "in the interest of making progress on the EU-facilitated dialogue to normalize Kosovo-Serbia relations."
It added that the United States was "disappointed and concerned" that the Kosovar government had rejected appeals "from its international partners" and called for "both parties [to] reduce inflammatory rhetoric and undertake concrete actions" to ensure regional stability.