Bulgaria's Interior Ministry says veteran investigative journalist Slavi Angelov has been attacked by unidentified assailants near his home in Sofia.
Angelov, the editor in chief of the weekly newspaper 168 Hours, was beaten with metal pipes late on March 17 and is now in the hospital, the ministry said on March 18.
Angelov told journalists from his hospital bed that he was attacked by two men wearing masks. He said a third masked man filmed the assault on a mobile phone.
The assailants did not take anything from Angelov, although he was carrying his laptop at the time, police said.
"Most likely it is an attempted assassination," said Ivaylo Ivanov, the Interior Ministry's chief secretary.
The attack was condemned by the representative on freedom of the media for the Organization for Security and Cooperation in Europe (OSCE) and journalist organizations in Bulgaria, which ranks 111th out of 180 countries in Reporters Without Borders' 2019 World Press Freedom Index.
Calling the violent attack "an unacceptable act of intimidation" against Angelov, OSCE representative Harlem Desir said it took place "amid the backdrop of Bulgaria sliding down in media-freedom indices."
"Such brutal and bold attacks, if left unpunished, may create an atmosphere of fear within the media community," Desir said in a statement.
Earlier, the Bulgarian branch of the Association of European Journalists said that "the known facts lead to the conclusion that the beating was a contract one."
The group urged the Bulgarian authorities to "track down, put before justice, and punish not only the physical perpetrators but also the contractors of this monstrous crime."
Snezhana Todorova, head of the Union of Bulgarian Journalists, called the assault "the next attempt to shut the mouth, in the most brutal way possible, of a journalist who preaches the truth, looks for the truth in order to defend the freedom of speech in Bulgaria."
In recent months, Angelov has reported on cases such as the acquittal of a businessman brought to court over environmental damage to a campsite, and a prostitution ring said to operate in Bulgaria and Greece.
Angelov also wrote extensively about an investigation into gambling tycoon Vasil Bozhkov.
That investigation is focusing on allegations of serious financial violations in the gambling industry and Bozhkov's alleged links to the owner of the online casino Efbet.
Bozhkov was arrested recently on charges of tax fraud, attempted bribery, and racketeering.