Diplomatic relations between Bulgaria and Macedonia worsened this summer after a period of calm, Italian NGO Osservatorio Sui Balcani writes in a report.

The re-establishment of a Macedonian party in Bulgaria and the issuing of Bulgarian citizenship for a former Macedonian prime minister started the series of events, the report said.

Further negative developments were triggered by the statements of Bulgaria's Foreign Minister Ivailo Kalfin, the author of the report Francesco Martino said.

Kalfin said that Bulgarian support for Macedonia's EU entry was not going to be unconditional and Macedonia had to demonstrate good neighbourly relations and lack of agression towards Bulgaria's history and cultural heritage.

A number of analysts said such statements might have resulted from the upcoming presidential elections. Kalfin's statements was too strong to be ignored, the Italian report said.

The report said that in 1999 Macedonia and Bulgaria signed a bilateral agreement, in which they decided to refrain from involvement in the other country's domestic affairs.