BELGRADE — The Republic of Kosovo is preparing to take control Friday over the last two posts along its border with Serbia that are beyond its authority, an event that threatens to reignite tensions between the two adversaries.

While the two countries have recently made significant progress during talks on issues like property registry and trade, the planned takeover Friday is seen in Serbia, and by the Serbs who dominate in the northern part of Kosovo as a repeat of the events of July 25, when Kosovo sent police forces to take control over the border posts. Local Serbs reacted by forming roadblocks, shooting at troops sent by the NATO-led International peacekeeping force and burning a border post. A Kosovo police officer was killed.

“The people there will not accept it — Serbia cannot accept it,” Borko Stefanovic, Serbia’s lead negotiator in talks with Kosovo, said in an interview in his office at the Serbian Foreign Ministry. “We have a crisis coming up.”

“It can cripple the dialogue and have disastrous influence on the stability of the region,” he added.