The Trump administration has launched a concerted effort to force an unwilling Apple, Inc. to unlock two Apple iPhones owned by a Saudi military officer that shot dead three U.S. sailors in 2019.

Treasury secretary Steve Mnuchin on Wednesday added his voice to those of attorney general Bill Barr and president Donald Trump who on Monday and Tuesday both demanded Apple grant access to the iPhones owned by the late 2nd Lt. Mohammed Saeed Alshamrani. This man shot dead three U.S. Navy sailors and wounded eight others at Naval Air Station Pensacola in Florida on Dec. 6, 2019.  He was later shot dead by police. Apple has refused Barr and Trump's request.

Trump on Tuesday tweeted, ""We are helping Apple all of the time on TRADE and so many other issues, and yet they refuse to unlock phones used by killers, drug dealers and other violent criminal elements. They will have to step up to the plate and help our great Country, NOW! MAKE AMERICA GREAT AGAIN."

Mnuchin reminded Apple is had cooperated with law enforcement in the past and should do so again in this case. He also said other U.S. tech firms should improve their relationships with law enforcement agencies to better aid investigations at the state and federal level.

"I know Apple has cooperated in the past on law enforcement issues, and I expect they would continue ... to cooperate," said Mnuchin. He also said he supports Trump's tweet.

"I understand the president's view, and it is absolutely critical for our technology companies to cooperate with law enforcement," according to Mnuchin.

Mnuchin later told reporters at the White House that he had not discussed the issue with Apple and did not know the specifics at hand.

For its part, Apple has said that it has helped investigators in the Pensacola case by providing other data. It can't, however, access encrypted data stored on the shooters iPhones without building a "back door" or specialized software that will give law enforcement more access to Alshamrani's iPhones. Apple also pushed back at assertions it's not been that helpful in the Pensacola investigation.

"We reject the characterization that Apple has not provided substantive assistance in the Pensacola investigation," said Apple. "Our responses to their many requests since the attack have been timely, thorough and are ongoing."

On Monday, Barr asked for Apple's help with the investigation during a press conference. He said both of Alshamrani's iPhones are engineered to make it virtually impossible to unlock them without the password. He said it's very important to know with whom and about what Alshamrani' was communicating before he was shot dead by cops.

"We call on Apple and other technology companies to help us find a solution so that we can better protect the lives of Americans and prevent future attacks," he said.