Apple chief Tim Cook went public Wednesday in his battle with the FBI, saying that unlocking an iPhone in the name of fighting terrorism would be "bad for America."
"I think safety of the public is incredibly important -- safety of our kids, safety of our families is very important," Cook said during a television interview with ABC News.
"The protection of people's data is incredibly important, and so the trade-off here is we know that doing this could expose people to incredible vulnerabilities."
Apple is battling the US government over unlocking devices in at least 10 cases in addition to its high-profile dispute involving the iPhone of one of the San Bernardino attackers, court documents show.
Apple has been locked in a legal and public relations fight with the government in the San Bernardino case, where the FBI is seeking technical assistance in hacking the iPhone of Syed Farook, a US citizen, who gunned down 14 people with his Pakistani wife Tashfeen Malik in the California city in December.
When asked in the interview how he felt about Apple taking the stand with the chance information on Farook's iPhone might prevent another terrorist attack, Cook responded: "Some things are hard and some things are right. And some things are both. This is one of those things."
Cook maintained that the definite dangers of creating a way to crack into iPhone encryption trumped concerns about "something that might be there," adding he felt Apple was making the right choice.
"This (master key) is not something we would create," Cook said.
"This would be bad for America. It would also set a precedent that I believe many people in America would be offended by."
Google sides with Apple
Google chief Sundar Pichai on Wednesday added his voice to the ranks of Silicon Valley tech firms siding with Apple.
"When you create backdoors it leads to very, very bad consequences which always ends up harming users," chief executive Pichai said during a conference at Paris's Sciences Po university, as he waded into the controversy.
Facebook's Mark Zuckerberg said earlier this week that he was "pretty sympathetic" with Apple's quandary.
Meanwhile, America's top spy said in a National Public Radio interview on Wednesday that he supports the FBI's side in the high-profile battle with Apple.
Central Intelligence Agency Director John Brennan said the public would never accept criminals or terrorists having exclusive access to a physical storage box, and asked why an encrypted phone should be treated any differently.
"The FBI clearly has a legitimate basis to try to understand what is on a phone that is part of a very active investigation," Brennan said.
Other iPhones targeted
Apple revealed a list of cases where it is opposing the US Justice Department's requests in a February 17 letter to a federal judge in Brooklyn, where the company is challenging government efforts to access an iPhone in a drug trafficking case.
The letter said the requests sought Apple's assistance under the All Writs Act, a 1789 law which allows the courts broad authority to help law enforcement.
The letter said the cases were "similar in nature" but did not provide specifics about the government's requests.
It said the San Bernardino case was "even more burdensome" than the other requests because it would require the company to create new software to help investigators break into the iPhone.
Apple's letter to the Brooklyn judge cited nine additional cases where the government was seeking assistance in accessing iPhones or iPads.
Apple said this week that the California-based company it supports the idea of a panel of experts to consider access to encrypted devices if US authorities drop their legal battle.
The Apple response came after FBI Director James Comey explained the government's position, saying it was about "the victims and justice" in the San Bernardino attack, whose perpetrators are believed to have been inspired by Daesh.
"We don't want to break anyone's encryption or set a master key loose on the land," Comey said in a posting that appeared on the Lawfare blog and on the FBI website.
"The San Bernardino litigation isn't about trying to set a precedent or send any kind of message."