Apple lawyers say that the company has denied source code requests from Chinese authorities in the last two years.

On April 19, Bruce Sewell, Apple's general counsel, told a congressional hearing that the company has never released any user data to government authorities of any country.

In February, the FBI has filed documents in a federal court that wants Apple's technological assistance in unlocking an iPhone 5c related to San Bernardino shootings in 2015. The iPhone 5c was used by Rizwan Farook, the gunman responsible for killing 14 and wounding another 22 people.

Law enforcement officials believe that the iPhone 5c in question may unravel more information regarding the said shootings.

Captain Charles Cohen, a commander in the Indiana State Police, also backs claims that in the past Apple has been secretly cooperating with the China, and has given the source code to its government.

However, Apple denies the allegation and suggests that the U.S. Department of Justice (DOJ) is accusing Apple so that they can get assistance in unlocking the iPhone 5c.

"I want to be very clear on this. We have not provided source code to the Chinese government," said Sewell.

Security and technology experts believe that if the FBI is successful in getting Apple to unlock the iPhone, then other government agencies across the world may also make similar requests if the need arises. This could negatively impact the sales of Apple products, thus, resulting in financial loss to the company.

The FBI had dropped the case in March saying that the agency has found a third-party that could break into Apple iPhones. However, it seems that the entity hired by the FBI was unsuccessful in unlocking the iPhone 5c, because the FBI is seeking Apple's assistance again.

The security systems in mobile devices such as smartphones and tablets have been increasing, which helps in keeping customer data safe. However, law enforcement says that the advances in security technology are also posing a threat to the national security as criminals can successfully hide data in smartphones and potentially paralyze investigations.

Thomas Galati, the chief of intelligence at the New York Police Department, says that from October 2015 to March 2016 investigators in his team have failed to unlock 67 Apple devices. These iDevices are linked with 44 violent crimes, which include homicides, rapes and shooting of an officer.