Zelensky and Rafael Grossi met in the southern region of Zaporizhzhia ahead of the IAEA chief's visit to the nuclear power plant.

Europe's largest nuclear power plant was captured by Russia a year ago.

Grossi will be travelling to the nuclear plant for the second time since Moscow invaded Ukraine in February 2022.

"Without the immediate withdrawal of Russian troops and personnel from the Zaporizhzhia nuclear plant and adjacent territory, any initiatives to restore nuclear safety and security are doomed to failure," Zelensky told Grossi, according to a statement from the presidency.

Their meeting took place on the territory of the Dnipro hydroelectric power plant, which has been damaged by Russian strikes.

Zelensky told Grossi that staff at the Zaporizhzhia plant were under "constant pressure" and added that the Russians did not comply with safety rules and interfered in the plant's operations.

Grossi is expected to visit the nuclear plant later this week.

"I met Zelensky today in Zaporizhzhia City and had a rich exchange on the protection of the Zaporizhzhia NPP (nuclear power plant) and its staff," he said on Twitter earlier Monday.

"I reiterated the full support of the IAEA to Ukraine's nuclear facilities," he said.

Earlier on Monday, Zelensky said he visited Ukrainian military positions in the region of Zaporizhzhia.

"I am honoured to be here today, next to our military," Zelensky said on social media, posting a video of himself and Ukrainian servicemen.

"We will definitely win."

During the trip, the Ukrainian president visited a local command post, decorated policemen and servicemen and inspected buildings damaged by Russian forces, the presidency said in a statement.

Zelensky's visit to Zaporizhzhia came after he visited the southern region of Kherson last week as well as military positions in the eastern Donetsk region.