U.S. President Donald Trump said Tuesday that Taiwan had agreed to buy 30% of the gas from a proposed liquefied natural gas project in Alaska.

"Taiwan has just agreed to buy 30% of the gas coming off the pipeline for the next 20 years," Trump said at a rally in Alaska. "That guarantees a success."

His latest remarks follow repeated claims earlier this month that South Korea had agreed to join the $50 billion Alaska LNG project, even as Seoul maintained that its participation had not been finalized. "We'll also invest $4.4 billion into the project, on top of $50 billion already committed by South Korea to Alaska," Trump said.

However, the terms of the Taiwan deal cited by Trump were not immediately clear.

Last year, Taiwan's state-owned energy company CPC Corp reportedly reached an agreement with Alaska Gasline Development Corp to purchase LNG and invest in the pipeline project.

Taiwan, home to critical semiconductor giant TSMC, has seen energy demand climb due to AI-related growth. However, the island relies on imports for more than 90% of its energy supply and this summer projected its average electricity demand growth rate through 2035 would exceed that of Japan and South Korea.

Taiwan's economic affairs ministry said that growth rate would climb by about 2.5% a year, the second-highest forecast in its history. The democratically self-ruled island is still waiting on major new arms sales from the U.S.

Beijing considers Taiwan part of its territory.

Glenfarne, the developer of the Alaska LNG pipeline, told the U.S. government in a report this month the project aims to deliver its first gas in 2029.

Trump has also stepped up pressure on South Korea over its participation in the project, warning earlier this month that he would charge the country more and threatened to double the charges if Seoul failed to sign soon, without specifying what would be doubled. That prompted speculation in South Korean media that he was referring to higher tariffs.

The White House, Taiwan's energy ministry and CPC Corp. did not immediately respond to CNBC's requests for comment.