The party of Bulgarian Prime Minister Boyko Borisov is set to unveil the name of its presidential nominee by September 20, but might not announce it even later, Borisov's deputy has made clear.

Presidential elections are due on November 06. The Bulgarian Socialist Party (BSP), the biggest opposition force, is the only one which has announced a candidate, amid uncertainty whether Borisov intends to run himself.

In an interview with public broadcaster BNT, GERB deputy head Tsvetan Tsvetanov has explained that the party has already chosen its contender.

Asked what has prompted the party to delay the announcement, initially scheduled for mid-September, he has cited the desire to make sure "the government, the local administration, and Parliament will work undisturbed and I think we succeeded."

GERB officials have already pointed to the need  to "preserve stability" to explain their decision not to unveil their presidential candidate.

"I think sometime between September 20-22 and October 2 is a normal deadline for the presidential pair to be unveiled."