James Martin/CNET

Silent Circle shuttered its encrypted e-mail service on Thursday, the second such closure in just a few hours in an apparent attempt to avoid government scrutiny that may threaten its customers' privacy.

Silent Circle, which makes software that encrypts phone calls and other communications, announced in a company blog post that it could "see the writing on the wall" and decided it best to shut down its Silent Mail feature. The company said it was inspired by the closure earlier Thursday of Lavabit, another encrypted e-mail service provider that alluded to a possible national security investigation.

"We have not received subpoenas, warrants, security letters, or anything else by any government, and this is why we are acting now," the company explained in its post. "We'd considered phasing the service out, continuing service for existing customers, and a variety of other things up until today. It is always better to be safe than sorry, and with your safety we decided that the worst decision is always no decision."

The company said it would continue to support its Silent Phone, Silent Text, and Silent Eyes teleconferencing platform, assuring users it collects no encrypted data or metadata about conversations.

"Silent Mail was a good idea at the time, and that time is past," the company said.

Earlier Thursday, Lavabit, an encrypted e-mail service linked to NSA whistleblower Edward Snowden, hinted at a U.S. government investigation as the reason for its closure. Ladar Levison, the owner of Lavabit, said he was "forced to make a difficult decision" and that he would like to discuss the circumstances but was prevented from doing so because "Congress has passed laws that say otherwise."

Lavabit, which uses encryption to prevent messages from being read by anyone other the sender or recipient, was the service Snowden allegedly used to send a message to a Human Rights Watch representative in July.