The Ukrainian leader made the comment on Saturday at a news conference in Kyiv, while standing alongside visiting Canadian Prime Minister Justin Trudeau.
He was responding to a question about Russian President Vladimir Putin’s statement a day earlier that Ukraine’s counteroffensive had started and that Ukrainian forces were taking “significant losses”.
Zelenskyy said that “counteroffensive, defensive actions are taking place in Ukraine. I will not speak about which stage or phase they are in.”
“I am in touch with our commanders of different directions every day,” he added, citing the names of five of Ukraine’s top military leaders.
“Everyone is positive. Pass this on to Putin.”
Top Ukrainian authorities have stopped short of announcing a full-blown counteroffensive was underway, though some Western analysts have said fiercer fighting and reported use of reserve troops suggests it was.
In his nightly video address, Zelenskyy provided few details while urging troops to keep fighting.
“Thank you to all those who holds their positions and those who advance,” he said, citing the eastern and southern fronts, where fighting is heaviest.
Ukraine’s general staff said its forces had repelled enemy attacks around Bakhmut and Maryinka, sites of heavy clashes in the east. Russian forces, it said, “continue to suffer heavy losses which they are trying to conceal”.
Deputy Defence Minister Hanna Maliar made it plain on Telegram that the military would issue no statements until battlefield positions became clear.
“Ask yourself this… am I prepared to receive information about the liberation of this or that town not when our troops enter it, but once they establish a stronghold?” she wrote.
Ukraine has said for months it plans to conduct a major counter-offensive to recapture land occupied by Russia in the south and east. But it is enforcing strict operational silence for now and has denied it has begun the main operation.
With scant independent reporting from the front lines, it has been difficult to assess the state of the fighting.
‘Significant’ operations
The British Ministry of Defence meanwhile said Ukraine had conducted “significant” operations in several eastern and southern parts in the last 48 hours, with Russian defences breached in places.
“In some areas, Ukrainian forces have likely made good progress and penetrated the first line of Russian defences. In others, Ukrainian progress has been slower,” it said, also characterising the Russian military’s performance as mixed.
“Some [Russian] units are likely conducting credible manoeuvre defence operations while others have pulled back in some disorder, amid increased reports of Russian casualties as they withdraw through their own minefields,” it said.
Ukraine’s counter-offensive is expected to use thousands of troops that have been trained and equipped by the West, but Russia has built huge fortifications in occupied territory to prepare, while Kyiv also lacks air supremacy.
The south is seen as a key strategic priority for a Ukrainian push that could aim to recapture Europe’s biggest nuclear plant and cut the Russian land bridge to the occupied Black Sea peninsula of Crimea, dividing Russian forces.
The fighting there has drawn renewed attention following the destruction of the Russian-controlled Khakova dam along the Dnieper River on Tuesday.
The flooding from the breached dam has forced thousands to flee their homes and sparked fears of humanitarian and environmental disasters. Ukraine accuses Russia of blowing up the dam, while Moscow says Kyiv fired on it.
Trudeau, the first foreign leader to visit Ukraine since the attack on the dam, offered up monetary, military and moral support.
He pledged 500 million Canadian dollars ($375m) in new military aid, on top of more than 8 billion Canadian dollars ($6bn) that Canada has already provided since the war began in February 2022, and announced 10 million Canadian dollars ($7.5 million) for humanitarian assistance for the flood response.
Trudeau said the dam’s collapse was “a direct consequence of Russia’s war,” but he did not blame Moscow directly.
In other developments, the British government also said it will give 16 million pounds ($20m) in humanitarian aid to those affected by the flooding.
Most of the money is being channelled through international organisations such as the Red Cross and the United Nations, and the United Kingdom is also sending boats, community water filters, water pumps and waders to Ukraine.
German Chancellor Olaf Scholz meanwhile said on Saturday that he wanted to continue speaking with Putin and plans to do so again “soon”.
Scholz has spoken several times by phone with Putin since the invasion.
The chancellor said the basis for a “fair peace” between Russia and Ukraine is the withdrawal of Russian troops.
“That’s needs to be understood,” he said.