BELGRADE, Serbia (AP) — U.S. President Donald Trump's special envoy for Kosovo and Serbia on Tuesday urged the new Kosovo government to abolish punitive tariffs on Serbian goods that have blocked negotiations between the two Balkan rivals.

Richard Grenell, who is the U.S. ambassador to Germany, said that “we expect the tariffs to be dropped immediately."

"We made clear to all the (Kosovo) party leaders that dropping the tariffs was in the best interest of Kosovo and its economy, and the desire to attract new businesses,” he said in an emailed statement to The Associated Press.

A European Union-mediated dialogue between Serbia and Kosovo over normalizing ties stalled after the previous Kosovo government imposed the 100% taxes on Serbian goods in protest of Serbia's blockade of Kosovo in the International Red Cross and other international organizations.

Kosovo's parliament on Monday voted in a new prime minister after nearly four months of talks between the country's two main parties.

Albin Kurti, the new premier, told the parliament the tariffs won't be dropped and that Kosovo will insist on "reciprocity" in its trade with Serbia. He gave no further details.

Grenell last month brokered tentative deals to resume railway and air links between the two states that have been suspended for 21 years.

“We are making historic progress," Grenell said. “There are more announcements coming soon because both sides are eager to move forward. These moves will create a better life for the people of the region.”

Serbia's intervention against Kosovo's independence-seeking ethnic Albanians in 1998-99 prompted NATO to intervene and stop the conflict.

Serbia and its allies Russia and China don't accept Kosovo's 2008 declaration of independence, although Serbia's former province has been recognized by about 100 countries, including the U.S. and most EU nations.