Ukrainian President Volodymyr Zelenskyy is expected to visit France for separate talks with French President Emmanuel Macron and US President Joe Biden.

Zelenskyy has attached importance to the series of international conferences discussing aid to Ukraine and other issues scheduled for June, suggesting the month will be crucial.

Zelenskyy is set to attend an event on Thursday to commemorate the 80th anniversary of the D-Day landings that helped end World War Two.

The French presidential office says Macron and Zelenskyy will hold talks in Paris on Friday.

Multiple media outlets have reported on the possibility that France will disclose plans to dispatch military trainers to Ukraine.

Meanwhile, Italy will be hosting a Group of Seven summit starting June 13, while Switzerland will set the stage for an international conference to develop a peace process for Ukraine, advocated by Zelenskyy, starting June 15.

In a video address on Tuesday, Zelenskyy said, "It is only the beginning of June, but these are already the weeks that will determine the whole summer and, in many ways, this year."

Against this backdrop, Russian Foreign Minister Sergey Lavrov, touring Africa, held talks with his Republic of Congo counterpart on Tuesday.

Lavrov played down the significance of the Swiss meeting, saying neither Republic of Congo's president nor the leaders of China, India, Brazil or South Africa believe talks without the participation of Russia make sense.