Blockchain website. Blockchain

Apple Inc. (NASDAQ:AAPL) has pulled the only bitcoin wallet app available to Apple users from its App Store.

Blockchain, the world’s most popular bitcoin wallet currently, used by 1 million users worldwide, was removed from the Apple App Store without a specific reason on Wednesday, said Nicolas Cary, the CEO of Blockchain. While existing users can still run the app on their iPhones and Macs, they will not be able to get software updates any longer, Wired reported.

Apple could not be reached for comment, but the email Cary received from the tech giant said the app was “removed from the App Store due to an unresolved issue.” This is the second time that Blockchain, which was released in the App Store in April 2012, has been removed. It is not clear whether the app will be readmitted like it was last time.

Blockchain became the only bitcoin wallet app available to Apple users after two other wallets, BitPak and Coinbase, were successively pulled from the App Store last year. The latter survived less than a month on Apple’s turf.

There has been speculation that Apple is dumping bitcoin wallets as the popular virtual currency becomes increasingly regulated internationally, but some, including Blockchain’s Cary, believe that Apple views bitcoin as a potential competitor.

“I think that Apple is positioning itself to take on mobile payments in a way they haven’t described to the public and they’re being anti-competitive,” Cary said, according to Wired.

Google Inc. (NASDAQ:GOOG) appears more cooperative as bitcoin struggles to get past its recent setbacks abroad and in the U.S., as both Blockchain and Coinbase apps are still available on the Android.

“We’re totally cool with Google,” Cary said.