BEIJING (Reuters) - Chinese tech giant Huawei has started allowing customers to register their interest in an upcoming smartphone model it has yet to describe, stoking anticipation that the latest version of its high-end P series phones is on its way.

The company jumped back into the premium smartphone market last year with its Mate 60 series, a launch celebrated by state media as a triumph over U.S. sanctions on the firm. The launch has also been blamed for a steep decline in Apple's iPhone sales in China. 

Speculation has built up in recent months that Huawei will soon launch the P70, which is expected to, like the Mate 60, contain an advanced China-made chip.

Huawei's P series has advanced cameras and is known for its sleek design, while the Mate series, also high-end, emphasises performance and business features.

A Thursday product launch for a smart car model and laptop did not mention phones, disappointing legions of fans who complained online.

But on Friday, checks made by Reuters at three Huawei stores in Beijing found that interested buyers could register to receive information about a phone without making a deposit. Registered customers will be notified about the phone's specs and colours in due course, sales staff said.

The Mate 60, notably launched during a trip by U.S. Commerce Secretary Gina Raimondo to China, did not involve any prior advertising or disclosure of specifications, prompting some users and companies to tear down the phones as they sought to work out its capabilities.

"Huawei kills two birds with one stone," Will Wong, an analyst with research firm IDC, said of this tactic. He noted that the firm could maintain a lower profile amid U.S.-Sino trade tensions while generating an air of mystery and excitement over the launches.

Archie Zhang, a smartphone analyst at Counterpoint Research, noted that the availability of stock has been a significant constraint for the Mate 60 and would likely be so for the P70 as well.

Huawei has had to slow production for Mate 60 phones due to production constraints and the need to prioritise manufacturing of artificial intelligence chips, sources have said.