French President Emmanuel Macron fears the "worst is yet to come" in the Ukraine war following a telephone call Thursday with Russian President Vladimir Putin, according to media reports.

Elysee officials told reporters that Putin expressed "his great determination" to continue his military offensive with the objective "to take complete control of Ukraine," said a report by BFMTV news.

The 90-minute exchange initiated by the Russian head of state failed to yield any assurance from Russia to slow the military offensive even as new talks between Moscow and Kyiv began on the Belarusian-Polish border late Thursday.

Putin also threatened to increase his demands with Kyiv to achieve Moscow's objective of demilitarization and a neutral status for Ukraine, the report said.

Macron reportedly told Putin he was "lying to himself" and making a "major mistake" by choosing to continue the war as it will result in international sanctions which would weaken and isolate Moscow for a very long time.

But Putin told Macron that the Russian army's operations were developing "according to the plan" and they would "get worse" if the Ukrainians did not accept its conditions, according to another report by French newspaper Le Monde.

Macron afterward shared details about the call with Ukrainian President Volodymyr Zelenskyy.

Foreign Minister Jean-Yves Le Drian evoked sentiments similar to Macron's earlier when he said the worst is yet to come as major Ukrainian cities are at risk of falling under the Russian siege.