Police in southwest Bosnia have stopped five buses containing migrants and refugees from Sarajevo from going to the Salakovac asylum centre near the city of Mostar.
They intercepted the buses when they arrived in Konjic, between Sarajevo and Mostar. Cantonal police then told them they cannot go any further, N1 media reported.
Thaci said earlier that he would respond to alleged threats from Serbia "with guns, just like 19 years ago."
Vucic, who was today in Mostar, Bosnia-Herzegovina, said that it was "up to us to respond to Thaci's mention of guns calmly," and then recalled that "it was not his guns, but some foreign planes that were destroying Serbia."
The chairman of the presidency of Bosnia and Herzegovina, Dragan Covic, announced on Wednesday that a planned working lunch in the town of Mostar with presidency members and the country's political party leaders has been cancelled.
The official reason given by Covic's office was the "inability of the participants to arrive".