U.S. national-security adviser John Bolton has called on Kosovo and Serbia to settle their longstanding disputes, amid heightened tensions between the two Balkan countries over Pristina's decision last week to impose a 100 percent tax on Serbian products.
"The time is now for Kosovo and Serbia to reach an agreement," Bolton tweeted after meeting with Kosovo's President Hashim Thaci at the White House on November 27.
He also wrote that the United States "stands ready to help both parties achieve this historic goal."
"There's a historic chance in dialogue that should not be missed for both countries," Thaci tweeted, adding that this would help push forward Kosovo's efforts to join NATO, the EU, and the United Nations.
Relations between Pristina and Belgrade have been tense since Kosovo declared independence from Serbia in 2008.
Although more than 110 countries recognize Kosovo, Serbia does not.
Both countries have been told they must resolve their differences in order to make progress toward EU membership, but EU-sponsored normalization talks have been stop-and-go in recent months.
On November 21, Pristina slapped a 100 percent tax on imports from Serbia -- and Bosnia-Herzegovina -- in retaliation for what it said were Belgrade's efforts to undermine the young republic on the international stage.
The move drew angry reactions from Belgrade and Sarajevo and calls from the European Union and the United States to revoke the measure.
It also prompted the mayors of four predominantly ethnic Serb municipalities in northern Kosovo to resign on November 27, while hundreds of demonstrators rallied in North Mitrovica against the tariff.
The meeting between Bolton and Thaci came a day after the Kosovar president held talks with U.S. Secretary of State Mike Pompeo in Washington.
During the meeting, Pompeo urged Kosovo to rescind the tariffs on Serbian products and to work with Belgrade to "avoid provocations and deescalate tensions," the State Department said in a statement.
"Normalizing relations between Kosovo and Serbia is the only way to clear the path to both countries' future integration into the Western community of nations," it also said.