Slovak Prime Minister Robert Fico, 59, was shot and hit in the abdomen after a gunman opened fire following a government meeting in central Slovakia, Slovak news media reported on Wednesday.
Fico was initially in a life-threatening condition and was transported by helicopter to Banska Bystrica hospital.
After several hours, the deputy prime minister told the BBC that Fico was not in a life-threatening situation anymore.
"I was very shocked ... fortunately, as far as I know, the operation went well - and I guess in the end he will survive ... he's not in a life-threatening situation at this moment," Tomas Taraba said.
A Reuters witness heard several shots fired after the meeting in Handlova northeast of the capital Bratislava. Police detained a man and security officials pushed someone into a car and drove off, the witness said.
An assasination attempt was carried out on Slovak Prime Minister Robert Fico, a Slovak interior ministry spokesperson confirmed to Reuters by telephone.
Fico was conscious when he was taken to a hospital in the town of Handlova and was treated for bullet wounds, a hospital spokesperson told Reuters by email.
Slovak news agency TASR quoted parliamentary vice-chairman Lubos Blaha as saying Fico had been shot and hurt. Broadcaster TA3 reported four shots were fired, one hitting Fico, 59, in the abdomen.
The Reuters witness said he saw security officials pushing someone into a car and driving off.
The government office could not immediately be reached for comment.
The Slovak emergency service dispatched a helicopter to a 59-year-old man in Handlova after receiving information that he had been shot, it said in a post on Facebook, adding that the action was still underway.
Reactions and background to the shooting
President Joe Biden condemned the attempted assassination of Fico and said the US Embassy was ready to assist the government there, according to a statement released by the White House.
"I am alarmed to hear reports of an attack on Slovak Prime Minister Robert Fico," Biden said. "We condemn this horrific act of violence. Our embassy is in close touch with the government of Slovakia and ready to assist."
Ursula von der Leyen, President of the European Commission, condemned what she described as a vile attack on Fico.
British Prime Minister Rishi Sunak said he was shocked to hear news of the attack on Fico. "Shocked to hear this awful news. All our thoughts are with Prime Minister Fico and his family," Sunak said on X.
Ukrainian President Volodymyr Zelensky condemned the shooting of Fico, calling the attack "appalling."
"Every effort should be made to ensure that violence does not become the norm in any country, form, or sphere," he said on X.
Russian President Vladimir Putin called the shooting a "monstrous" crime.
"There can be no justification for this monstrous crime. I know Robert Fico as a courageous and strong-minded man. I very much hope that these qualities will help him to survive this difficult situation," Putin said in a telegram to Slovak president Zuzana Caputova.
Putin also wished Fico "a speedy and full recovery".
The Slovak government was meeting in Handlova, 190 km (118 miles) northeast of Bratislava, as part of a tour of the country's regions after coming to power late last year.
Fico returned as prime minister of the central European country, which is a member of the European Union and NATO, for the fourth time last year after shifting political gears to appeal to a changing electorate.
During a three-decade career, Fico has moved between the pro-European mainstream and nationalistic positions opposed to European Union and US policies. He has also shown a willingness to change course depending on public opinion or changed political realities.
Following the shooting, Slovakia's biggest opposition party called off a planned protest against government public broadcaster reforms set for Wednesday evening.