A majority of Americans support the US government's efforts to force Apple to help unlock an iPhone in the probe of last year's deadly San Bernardino attacks, a poll showed Monday.

The Pew Research Center survey found 51 percent of respondents supported the effort to require Apple to help unlock the iPhone, while 38 percent said Apple should not unlock the phone to ensure the security of its other users. Eleven percent did not offer an opinion.

In the poll taken from February 18-21 -- shortly after news broke about the standoff -- 75 percent in the survey said they were aware of the deadlock, with 39 percent saying they had heard "a lot" and 36 percent indicating they heard "a little" about it.

Support for the government's case was highest among the older poll respondents, by a 54-27 percent margin among those 65 or older.

There was little difference between Democrat and Republican respondents, but independents were nearly split on the issue, with 42 percent siding with Apple to 45 percent for the government.

Smartphone owners were in support of the government by a 51-40 percent margin, but among iPhone owners the support was a bit lower at 47-43 percent.

The researchers surveyed 1,002 American adults by mobile or landline telephone. The margin of error for the full sample was estimated at 3.7 percentage points.

US authorities are seeking to enforce an order to require Apple to provide technical assistance to unlock the iPhone of one of the attackers. Apple and its supporters argue that complying would set a precedent that would weaken security for all users.

Apple encryption fracas about 'victims and justice': FBI chief
Washington (AFP) Feb 22, 2016 - A court order the US government requested to force Apple to unlock an iPhone linked to the San Bernardino shooting rampage is about "the victims and justice," FBI Director James Comey said.

In his first public remarks since Apple CEO Tim Cook said he would fight the federal magistrate's order, Comey said the Justice Department's request is simply about gaining access to the locked phone.

"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 lawfareblog.org site late Sunday.

Investigators want to hack into an iPhone belonging to the late Syed Farook, a US citizen who along with his wife Tashfeen Malik went on a shooting rampage in San Bernardino, California that killed 14 people on December 2.

Apple claims that cooperating with the FBI probe would undermine overall security for its devices.

"The San Bernardino litigation isn't about trying to set a precedent or send any kind of message," Comey said. "It is about the victims and justice."

According to Comey, the "particular legal issue is actually quite narrow... We simply want the chance, with a search warrant, to try to guess the terrorist's passcode without the phone essentially self-destructing and without it taking a decade to guess correctly. That's it.

The phone may or may not hold important clues. "But we can't look the survivors in the eye, or ourselves in the mirror, if we don't follow this lead," he wrote.

This case highlights the new technology that creates "tension between two values we all treasure: privacy and safety. That tension should not be resolved by corporations that sell stuff for a living.

"It also should not be resolved by the FBI, which investigates for a living. It should be resolved by the American people deciding how we want to govern ourselves in a world we have never seen before."

Finding "the right place, the right balance, will matter to every American for a very long time" said the head of the Federal Bureau of Investigation.

Both Apple CEO Tim Cook and Comey have been invited to testify about encryption on Capitol Hill.