Tensions between Serbia and Kosovo soared on Thursday after Kosovo slapped a 100 percent tax on all goods imported from Serbia.
Serbian President Aleksandar Vucic blamed the European Union and the West for allegedly failing to prevent Kosovo's move.
He also claimed Kosovo's special troops were prepared to attack the Serb-populated regions of Kosovo. The claim was denied by Kosovo authorities.
Vucic, a former ultranationalist who now seeks EU membership, said the West has always blamed "both sides" for tensions in Kosovo, "while in fact they support only one, and that is not Serbia."
"There is no end to it," said Vucic referring to the alleged Western double standards. "Should we allow for the Serb children to have no milk from Serbia to drink? . We will fight and we will not let that to happen so easily," he warned.
After a bloody war in 1998-99 war that was only stopped after a U.S.-led NATO intervention, Kosovo declared independence from Serbia in 2008. Serbia and its ally Russia do not recognize Kosovo's statehood, while the U.S. and most Western countries do.
The EU, which is mediating the Serbia-Kosovo peace talks, has told the two sides they must normalize relations as a precondition to entering the bloc.
Despite diplomatic tensions between Serbia and Kosovo, business ties have grown and Serb imports to Kosovo amount to about 400 million euros ($460 million) a year, while Kosovo's exports to Serbia are much lower. The latest taxes are likely to hurt mostly Serbs who live in the north of Kosovo.
Kosovo's prime minister, Ramush Haradinaj, said he sent a letter to the EU's foreign policy chief, Federica Mogherini, and all ambassadors in Kosovo to clarify the tariffs hike.
"I believe that such steps (taxes) on products coming from Serbia should be permanent until the recognition," he told a Kosovo parliament session.
Vucic said that Haradinaj's stand is the result of "big (Western) powers that are behind this."
"We have to prepare ourselves for a long and tough battle because we will not recognize (Kosovo's) independence," he said.
Maja Kocijancic, the spokeswoman for Mogherini, said Kosovo violated the regional trade agreement, but reiterated a general EU position that the two sides should refrain from provocations and turned to EU-mediated dialogue.
"We call on the two leaderships to bring to an immediate end these provocations and focus on completing normalization of relations without further preconditions," she said.
Although seeking EU membership, Serbia has lately been drifting toward Russia.
Llazar Semini in Tirana, Albania, and Jovana Gec in Belgrade, Serbia, contributed to this report.