SEOUL — Huawei launched a new flagship smartphone Thursday, in what analysts say could potentially be its last one if U.S. sanctions continue to bite, even as sales at home surge on patriotic buying.

Huawei’s domestic smartphone sales have soared to dominate nearly 50 percent of China’s market in some months of this year, analysts say, bolstered by patriotic support from Chinese shoppers as the company came under siege from Washington.

Since Sept. 15, U.S. sanctions have cut Huawei off from key suppliers of semiconductors, all of which require U.S. technology for their operations. Its new Mate 40 phones will be outfitted from Huawei’s stock of prepurchased processors, analysts say, with no immediate avenue for replenishing its supply.

Jeff Pu, a technology analyst at GF Securities, estimates that Huawei has enough chipsets now to make 80 million smartphones, which could last the company through March or April.

“After that, there’s no chipsets, so the smartphone shipments will come down to zero,” he said.

Neil Shah, an analyst at Counterpoint Research, said the outlook for Huawei depends largely on the U.S. election and if Washington eases its sanctions in coming months.

“If Biden wins, there could be some ray of hope for Huawei,” Shah said. “If Trump wins, it doesn’t look that great for Huawei.”

Huawei’s chip shortage will probably limit the availability of the Mate 40, which would otherwise have been a strong contender in global sales against the new iPhone 12. Huawei’s smartphones in recent years have equaled or even surpassed iPhones in technological features.

A Huawei spokesman declined to comment on chipset supply on Thursday.

In August, Richard Yu, CEO of Huawei’s consumer business group, said in a speech that the company’s smartphone sales this year may decline due to sanctions.

“It’s the second round of sanctions this year,” he said. “Our chips can’t be manufactured, so it’s been really difficult. Recently, we’ve been in a period of shortage.”

Domestic demand for Huawei phones, however, has boomed this year, as consumers have showed support for the company. Huawei has limited its supply of phones at retailers in recent months to conserve its chip supply, Pu said, pushing prices up.

Song Huawei, a 42-year-old resident of southwest Sichuan province, said by telephone on Thursday that he purchased a Huawei P40 Pro smartphone in September. He said that supplies of Huawei phones were tight in his town, and he had to wait two hours for the device to be brought to the shop from another site.

“I wanted to support domestic products,” Song said. “Everyone’s talking about how the U.S. is making trouble for Huawei.”

Deng Juan, a 32-year-old Beijing resident, said she also opted for a Huawei P40 smartphone this year, partly out of patriotism, after using iPhones for years.

“I originally used iPhones because they were fast,” she said by telephone on Thursday from Beijing. “But I discovered that Huawei phones are also fast and have other useful features, besides.”

Huawei briefly became No. 1 in global smartphone sales earlier this year, as coronavirus shutdowns around the world crimped Samsung’s sales.

Samsung retook its title in August, according to Counterpoint Research data, with the South Korean company accounting for 22 percent of global smartphone sales for the month compared to Huawei’s 16 percent.

Huawei remains embroiled in conflicts with the United States and other Western nations, including the detention of Meng Wanzhou, chief financial officer and daughter of Huawei’s founder, in Canada since December 2018. Sweden this month banned Huawei from its 5G network.

C.K. Lu, a Taiwan-based technology analyst at Gartner, said one scenario that would allow Huawei’s smartphone business to continue would be if the United States loosened sanctions to allow it to purchase off-the-shelf chipsets from third-party vendors. Even this is not allowed under the current restrictions.

“If the sanctions go on, there are no phones,” he said. “They just cannot produce anything.”

Lyric Li and Liu Yang in Beijing contributed to this report.