Prime Minister Boiko Borissov has admitted that his personal relations with President Georgi Purvanov have been strained. But this in no way undermines state institutions, he told private commercial Nova Televisia's morning show on September 11 2009.

"I've said enough about Purvanov's flight to Macedonia and today the pressing issue is European Union funds," Borissov said after returning from his two-day visit to EU's headquarters in Brussels.

Tension between Borissov and Purvanvon escalated after the September 5 tragedy when 15 Bulgarian tourists drowned after their boat sunk in Macedonia's Lake Ohrid.

Borissov sent a Government plane to bring survivors back to Bulgaria while Purvanov took another Government plane to visit the site of the tragedy himself.

After survivors returned to Sofia, reports said that their plane was held back an hour-and-a-half at Ohrid airport. Some media speculated that the plane could not take off because Macedonian authorities were waiting for Purvanov's plane to land so that he could meet survivors.

On September 7 2009, Borissov told private national bTV channel that Macedonian authorities were not culpable for holding back the plane.

"The plane could have come home an hour-and-a-half earlier but Macedonians are not to be blamed. Nothing would have harmed the image of a state institution if we had welcomed survivors together at Sofia airport where they would have been held for no more than five minutes," Borissov said.

Deputy Foreign Minister Marin Raikov, who was on the plane with survivors, told Bulgarian National Television: "Our goal was to get our fellow countrymen out of Ohrid as quickly as possible. One woman was on a stretcher and in a serious condition and we were in a hurry to bring her back to Bulgaria. She didn't know at the time that she had lost one of her children. The tragedy was complete."

"When we reached the airport, authorities said they would not allow us on the plane. I asked them why and they said that another plane was expected to land and that a meeting was scheduled to be held and after all this was over we would be allowed to go home."

On September 7 , the day of national mourning over the Lake Ohrid tragedy, the Presidency refused to comment on Borissov's and Raikov's comments.

On September 8, however, the presidency website published an article by Purvanov that was highly critical of Borissov's energy policy, calling him "obviously unprepared" for his meeting with Russian prime minister Vladimir Putin.

Purvanov expressed concern about what he called "the lack of competence" that the new Cabinet and Prime Minister Boiko Borissov had shown.

"There is a deficit of competence in the energy policy of this Government. The leader is not obliged to know everything but he must know enough to take a well-informed and motivated decision. There is always another route – the one of lack of expertise and covering this failure of will with fake scandals. But the question here is – until when and at what price?" Purvanov said.

Appearing on bTV on September 9, Nikola Kolev, head of Purvanov's cabinet, said that the article would have been less critical if it were not for the tension Borissov and other members of the cabinet had caused in the preceding days.

"The President's reaction was provoked and anyone who wants to check the genesis of the events would find the answer why," he said.