Serbia, backed by a fake news campaign, has accused Kosovo of planning "ethnic cleansing" of Kosovar Serbs, stirring bad memories of the Balkans wars.

"I hope that we will never have to use our army, but at the moment it is one of the options on the table, because we cannot watch a new ethnic cleansing [of Serbs] and new Storms," Serbia's prime minister, Ana Brnabic, told press in Belgrade on Wednesday (5 December).

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Ramush Haradinaj with Europe's foreign policy chief, Federica Mogherini, in the EU capital (Photo: consilium.europa.eu)

Operation Storm was the name of the last battle in Croatia's war of independence from Serbia in 1995, which led to the forced expulsion of over 150,000 ethnic Serbs.

Brnabic spoke amid Kosovo's plan to rename the 'Kosovo Security Force', a lightly-armed body of 4,000 men, into the 'Army of Kosovo' after a parliament vote on 14 December.

The army would "on 15 December, move to subjugate people only because they are Serbs", Brnabic added, referring to a Kosovar Serb enclave in north Kosovo, which remains under Serbia's de facto rule.

Serbia's president, Aleksandar Vucic, also poured fuel on the fire, saying: "Serbia cannot peacefully watch the destruction of the Serbian people".

Fake news

Their statements were accompanied by a fake news campaign in Serbia's state-controlled media.

"CIA sending a ship full of weapons and armaments" to be "distributed in south Mitrovica", one of Serbia's tabloids thundered on Wednesday, referring to a US spy agency and a Kosovo region abutting the Serb enclave.

"Unprecedented warmongering ... incredible lies, all of it," Petrit Selimi, Kosovo's former foreign minister, tweeted in response.

"We will not create the army for the north, it is a pure lie. Our army will serve in Afghanistan and Iraq [with Nato] to help world peace," Kosovo prime minister Ramush Haradinaj also said.

Serbia's propaganda onslaught echoed Russia's one in the Western Balkans, where Serb-language Russian media have been pumping out US-Kosovo conspiracy theories for years in a bid to stop EU and Nato enlargement by causing instability.

Russia also weighed in on Wednesday.

"We expect the international forces for Kosovo (Kfor) ... in the event of the appearance of such a structure (Kosovo army), [to] immediately take comprehensive measures to neutralise and disarm it," the Russian foreign ministry said.

Kfor is a 4,000-strong, 28-nation Nato peacekeeping force deployed in Kosovo in 1999 after the Serbia-Kosovo war, one of the bloodiest in the region, ended.

Part of its mandate is to "deter renewed hostility and threats against Kosovo by ... Serb forces", meaning that if Brnabic made good on her threat, then Serbia's forces might clash with Nato.

Tension spikes

The spike in tension comes amid Kosovo-Serbia talks to normalise relations and one day join the EU.

EU ambassadors agreed to open two new "chapters" in Serbia's accession talks also on Wednesday.

But the negotiations on normalising ties are in peril over a proposal to swap the main ethnic Serb enclave in Kosovo for an Albanian one in Serbia.

The idea, backed by Kosovo president Hashim Thaci, but opposed by Haradinaj, has caused turmoil in Kosovo politics.

It has also prompted a split in the region's Western protectors - the US has backed the idea, but Germany has warned that changing borders on ethnic lines could destabilise the Western Balkans.

Nato alarm

For his part, Nato head Jens Stoltenberg urged Belgrade and Pristina to "refrain from provocative steps and statements" on Wednesday.

He also criticised Kosovo, however.

"Such a step [the Kosovo army] is coming at a wrong time," he said in Brussels.

"What they have announced now is happening without consulting Nato allies and other countries, as well as without an inclusive process in Kosovo itself," he said.

Kfor would "have to reconsider its level of engagement in Kosovo" if Pristina went ahead, he added.

The army row comes after Haradinaj imposed 100 percent tariffs on imports of Serb goods, costing Serbia €42m a month in losses, according to Belgrade's calculation.

He did it when Serbia blocked Kosovo's bid to join the international police agency, Interpol, last month.

The EU and Nato have urged Haradinaj to back down, with Stoltenberg saying on Wednesday that it made dialogue "even more difficult".

But Albania voiced solidarity with its majority-ethnic Albanian neighbour the same day.

"In these abnormal conditions the tax should be seen as a political outcry and not of a trade war", Albanian prime minister Edi Rama told press while on a visit to Croatia.