Police raided the offices of Australia's national broadcaster on Wednesday over allegations it had published classified material, the second raid on a media outlet in two days, prompting complaints that the "outrageous" raids hindered media freedom.

The Australian Federal Police (AFP) said its officers carried out a search warrant at the head office of the government-funded Australian Broadcasting Corp. (ABC) in Sydney on Wednesday over a report known as the "Afghan Files."

That came a day after police raided the home of a News Corp editor, although the AFP said the raids were unrelated.

"It is highly unusual for the national broadcaster to be raided in this way," ABC Managing Director David Anderson said in a statement.

"This is a serious development and raises legitimate concerns over freedom of the press and proper public scrutiny of national security and defense matters," he said.

He added: "The ABC stands by its journalists, will protect its sources and continue to report without fear or favour on national security and intelligence issues when there is a clear public interest."

The AFP said the ABC raid was in relation to allegations it had published classified material and followed a referral from the chief of the Australian Defence Force and a former acting defense secretary in 2017.

The ABC raid was authorized by a court and based on evidence that provided "sufficient suspicion that a criminal offence has been committed", the AFP said in a statement. Australian law forbids officials from disclosing secret information, and the police warrants in both raids were based on a law enacted in 1914.

Six police descended on ABC's offices in Sydney armed with a warrant targeting three senior journalists and executives involved in a two-year-old investigative report.

In 2017, ABC obtained documents that showed Australian special forces had killed innocent men and children in Afghanistan and published them in a series of broadcasts.

The Australian police has a warrant to search through email systems in relation to the journalists and are searching "data holdings" between April 2016 and July 2017, ABC said. Police are also searching for article drafts, graphics, digital notes, visuals, raw television footage and all versions of scripts related to the stories.

ABC executive editor John Lyons said the search warrant demanded access to reporters' handwritten notes, emails, story drafts, footage and passwords, among other things -- going through a total of 9,214 documents.

"This is a really serious escalation of the attack on the free media, and that hits the public," he said as the raid continued. "I've never seen an assault on the media as savage as this."

Marcus Strom, president of the Media Entertainment and Arts Alliance trade union, said on his Twitter account the two raids were "just outrageous."

"Police raiding journalists is becoming normalized. It has to stop," he said.

The raid targeting the Canberra home of Annika Smethurst, the political editor of The Sunday Telegraph of Sydney, is related to a 2018 newspaper report that said Australian intelligence agencies wanted to carry out surveillance by accessing people's emails, bank accounts and text messages, domestic media reported.

The Sunday Telegraph's parent company News Corp called the raid on its employee "outrageous and heavy handed", and "a dangerous act of intimidation."

The Rupert Murdoch-controlled company said it had "the most serious concerns about the willingness of governments to undermine the Australian public's right to know about important decisions governments are making."

Australian Prime Minister Scott Morrison was reported as saying he believed in media freedom but that there were also clear rules about the use of classified information.

"​It never troubles me that our laws are being upheld," the Sydney Morning Herald quoted Morrison as saying.

Police said that controversial Home Affairs Minister Peter Dutton was not notified about the raids beforehand, and that the issues had been referred by two unnamed agency heads.

The raids came barely two weeks after Australia's conservative government won a May 18 election it was widely expected to lose, and which almost cost Dutton his seat.

The home affairs minister must authorize raids considered politically sensitive, according to guidelines on the police website.

Dutton denied involvement in the police investigations and said his office was notified after the raids were carried out.

"It is entirely appropriate they conduct their investigations independently and, in fact, it is their statutory obligation," Dutton said in a statement.

ABC staff posted footage and comments as the raid unfolded.

"This is a bad, sad and dangerous day for a country where we have for so long valued ... a free press," Lyons said on Twitter.

Peter Greste, director of the Alliance for Journalists' Freedom, said the raids were a serious issue for Australians who he said cared deeply about press freedom.

Greste is a former Al Jazeera reporter who was jailed with two colleagues in Egypt from 2013-2015 on national security charges brought by the Egyptian government.

"I'm not suggesting that Australia is about to become Egypt any time soon but what we are seeing seems to me to be on the same spectrum," he said.

Media reports said McBride was due in the Australian Capital Territory Supreme Court on June 13.

Shadow home affairs minister, the Labor party's Kristina Keneally, demanded an explanation for why the raids occurred.

Although the press in Australia can report largely free of political interference, strict defamation laws, court gag orders and state security statutes affect what can be said in print and broadcast.

Australia's Media, Entertainment and Arts Alliance union branded the raids a "disturbing attempt to intimidate legitimate news journalism that is in the public interest."

"Police raiding journalists is becoming normalised and it has to stop... it seems that when the truth embarrasses the government, the result is the Federal Police will come knocking at your door."

The BBC on Wednesday condemned overnight police raids on the headquarters of its Australian partner, describing it as a "deeply troubling" attack on press freedom.

"This police raid against our partners at ABC is an attack on press freedom which we at the BBC find deeply troubling," the British broadcaster said in a statement.

"At a time when the media is becoming less free across the world, it is highly worrying if a public broadcaster is being targeted for doing its job of reporting in the public interest."