Mobile carrier NTT Docomo said Tuesday five new smartphone models will allow investigative authorities to track the phones’ locations without users being aware of it.

A spokesman said the company has already been providing such data in some circumstances, mostly relating to crime investigations.

“If requested, we provided positional information using the GPS systems on phones to emergency services such as the police, ambulance services and the Japan Coast Guard, in line with proper guidelines,” the spokesman told The Japan Times.

Current phone models alert their users when the GPS locator is activated remotely.

Long-running guidelines by the Ministry of Internal Affairs and Communications required carriers to obtain the permission of users before providing such data to government entities. But in June 2015, the ministry dropped this requirement.

The spokesman said this change prompted the company to develop smartphone models that can be tracked discreetly.

The five Docomo Android models are the Xperia X Performance, the Galaxy S7 Edge, the Aquos Zeta, the Arrows SV and the Disney Mobile. The Galaxy S7 Edge will be available in stores from Thursday, while the rest will go on sale in June.

The spokesman added that smartphones already in use will be upgraded to offer similar abilities through a software update. The schedule for this is unknown at this stage, he said.

Some experts call the development alarming.

“This is an extreme invasion of privacy. It’s nothing like acknowledging merely which country you’re in,” said lawyer Tsutomu Shimizu. “Positional information is highly private because it reveals people’s movements. However, I understand that investigative authorities would need such information in certain situations, so there should be a law passed to help public understanding.”

He said it should be illegal for carriers to provide phone locations without informing users.

“It is a common practice and belief internationally that personal information should not be distributed to external organizations,” he said.

KDDI and SoftBank Corp. said they could not comment on the new guidelines, nor on what actions they may take.

“We are still assessing our future course of action,” said a KDDI spokesman.

A spokeswoman for SoftBank said: “We are now considering, based on the new guidelines, how to best cooperate with investigations.”

Investigative authorities will still need to obtain a court warrant before asking carriers to provide them with location data.

KEYWORDS Docomo, privacy, phones, NTT, telecoms