Zelenskyy made the comment in response to a question posed by a journalist regarding the claim made by Russian President Vladimir Putin on Friday that the counteroffensive was taking place and was already failing.
"It's interesting what Putin said about our counteroffensive. It is important that Russia always feels this — that they do not have long left, in my opinion," Zelenskyy said.
"Counteroffensive and defensive actions are underway in Ukraine — I will not go into detail about which stage," the Ukrainian president added.
The comments left it unclear whether the main thrust of the counteroffensive had already started or whether it was still in the preliminary stages.
The chances of Ukraine's government or military ever making such announcements explicitly or in any detail are low, because doing so is liable to harm their troops' chances in the field.
But observers have noted a significant uptick in military action in recent weeks, following months of hinting at a major counteroffensive by Ukrainian forces against well-entrenched Russian positions.
This week's destruction of the Nova Kakhova dam, for which Russia and Ukraine blame each other, could also have served to impede any Ukrainian plans to launch an amphibious assault across the Dnipro (or Dnieper) river.
While the UK's Ministry of Defense said on Saturday that Ukraine has "likely made good progress" on some fronts, the Russian Defense Ministry called attempts by Ukrainian forces to advance in the past 24 hours "unsuccessful."
Ukraine's top military leaders "are all in a positive mood," Zelenskyy told reporters as he sat next to visiting Canadian Prime Minister Justin Trudeau. "Pass that on to Putin."
Here are some of the other developments concerning Russia's war in Ukraine on Friday, June 10:
Scholz plans to speak to Putin 'soon'
German Chancellor Olaf Scholz said that he plans to speak with Russian President Vladimir Putin.
Scholz made the comments while speaking at the German Protestant Church Congress.
The chancellor said that he already spoke with Putin before the start of the war and intended "to do so again soon."
Scholz reiterated Berlin's position that the withdrawal of Russian troops would be a precondition for negotiations with Moscow, saying that this would be the only way to ensure a "fair peace."
"It's not reasonable to force Ukraine to approve and accept the raid that Putin has perpetrated and that parts of Ukraine become Russian just like that," Scholz added.
The chancellor said that he considered that Berlin had made the right decision in acting "in a coordinated manner" with its partners on Ukraine. He added that Germany felt committed to this principle since the start of the war early last year.
Responding to shouts from the crowd urging the chancellor to "negotiate," Scholz said: "Negotiating is OK. The question is: who negotiates with whom and about what?"
Justin Trudeau makes surprise visit to Kyiv
Canadian Prime Minister Justin Trudeau made a surprise to Kyiv on Saturday to show Canada's solidarity with Ukraine.
In Kyiv, Trudeau announced CA$500 million ($375 million, €350 million) in new military assistance for Ukraine.
"We will be there with as much as it takes, for as long as it takes," he told Ukrainian President Volodymyr Zelenskyy.
He also said Canada would seize a Russian-owned Antonov cargo plane that is stranded at Toronto's airport, and forfeit it to Ukraine.
Trudeau was accompanied by Canada's Deputy Prime Minister Chrystia Freeland, who is of Ukrainian descent and speaks the language.
The two Canadian politicians honored the memory of fallen Ukrainian soldiers at a memorial in central Kyiv.
Ukraine's Deputy Defense Minister Oleksandr Polishchuk handed Trudeau a container holding shrapnel from a rocket that fell on the Black Sea port city of Odesa, whole a group of Ukrainian soldiers who received training in Canada also spoke with the prime minister.
Zelenskyy thanked Trudeau and the Canadian parliament for assistance since the Russian invasion in February 2022.
"We are really thankful for everything you did for us, for our people, for refugees, for our army," he said.
The Canadian prime minister previously traveled to Ukraine in May last year.
Canada is home to one of the largest Ukrainian communities globally. It has provided Ukraine with military and financial aid since the outbreak of the war.
Russia to 'respond' after Iceland embassy closure
Russia said on Saturday it would respond after Iceland announced on Friday that it would close its embassy in Moscow, becoming the first country to do so.
"The decision taken by the Icelandic authorities to lower the level of diplomatic relations with Russia destroys the entire range of Russian-Icelandic cooperation," Russia's Foreign Ministry said in a statement.
"We will take this unfriendly decision into account when building our ties with Iceland in the future. All anti-Russian actions of Reykjavik will inevitably be followed by a corresponding reaction."
On Friday, Iceland's Foreign Ministry said it would suspend operations at its Moscow embassy because commercial, cultural and political relations were at an "all-time low" between the two countries. The embassy is set to shut on August 1.
Three killed in Odesa region drone attack
Three people have been killed and at least 26 others were injured after a Russian drone attack in the Ukrainian region of Odesa, Ukraine's military said on Saturday.
"At night, the enemy attacked Odesa Region with attack drones," the Ukrainian army said.
Although the drones were shot down by Ukrainian forces, falling debris from one of the downed drones hit an apartment building, causing a fire.
Separately, the Ukrainian air force said Russia had launched at least 35 drones and eight missiles at targets in Ukraine.
White House: Russia-Iran drone partnership is 'deepening'
The United States said the Russia-Iran military partnership appears to be "deepening."
Citing newly declassified information, the White House reported Moscow had received hundreds of drones, or Uncrewed Aerial Vehicles (UAVs), from Iran to strike Ukraine.
The information suggests that the drones were built in Iran, shipped across the Caspian Sea and used by Russia.
White House national security spokesman John Kirby said that the US is concerned Moscow is working with Tehran to manufacture Iranian drones within the Russian border.
A satellite image released by the White House indicates the location of a future drone factory in Russia.
While Iran claims the drone transfers occurred before the Ukraine invasion, Moscow denies deploying Iranian drones in Ukraine.
UK notes 'significant' military operations
Britain's defense ministry said "significant Ukrainian operations have been taking place" over 48 hours.
In its latest intelligence update on the war, the ministry on Saturday said Ukrainian forces "made good progress and penetrated the first line of Russian defenses" in some areas in the country's south. "In others, Ukrainian progress has been slower," it added.
Both Moscow and Kyiv reported fierce fighting on the front lines, suggesting Ukraine's counteroffensive was underway.
"We can state for sure that this offensive has begun," Russian President Vladimir Putin said on Friday.
Ukrainian President Volodymyr Zelensky spoke of "particularly difficult battles" and said he had discussed tactics and "achievements" with military leaders.
"We see your heroism and are grateful for every moment in your lives. Ukraine is as free as you are strong," he added.
Kyiv has always stressed that it would not comment on the start of its own offensive.
Poland used as a base for Nord Stream sabotage team — WSJ
The Wall Street Journal is reporting, German investigators were examining evidence suggesting that a sabotage team used Poland as a base to damage the Nord Stream pipelines.
The pipeline carrying gas from Russia to Germany was damaged in a series of explosions in September last year.
Investigators reconstructed the two-week journey of "Andromeda," a 50-foot-long white pleasure yacht suspected of being involved in the sabotage.
They discovered that the yacht deviated from its route, based on data from the yacht's radio and navigation equipment, satellite, and communication accounts.
Investigators attempted to match some of the DNA samples found on the yacht to "at least one Ukrainian soldier."
Ukrainian President Volodymyr Zelenskyy this week told German media that Ukraine did not attack Nord Stream pipelines.
German media in March identified the possible involvement of a yacht from a Poland-based company owned by Ukrainian citizens in the attack.
There has been no official comment from Germany's Federal Criminal Police Office.
ab, zc, ns/lo, msh (AP, AFP, dpa, Reuters)