On Thursday, Ukraine's President Vladimir Zelensky said he would not participate in the G20 summit if Russian President Vladimir Putin was there.
"My personal position and that of Ukraine is that if the leader of Russia participates, then Ukraine will not," the Ukrainian agency UNIAN quoted Zelenskyy as saying.
At the same time, he added that Kyiv was prepared for the upcoming summit, set for November 15-16.
On Thursday, Zelenskyy discussed the G20 summit with Indonesian counterpart Joko Widodo by telephone.
Earlier, Bloomberg reported that the Indonesian Foreign Ministry had so far confirmed the participation of 17 heads of state in the summit.
Jakarta avoided naming the countries that remained undecided. Neither Russia nor Ukraine, whose president was invited to attend although their country is not a member of the G20, has announced whether their leaders will participate in the meeting.
The G20 is an informal organization that unites the largest economically developed and developing countries.