Japan, South Korea and other countries want to partner with the United States in a "gigantic" natural gas pipeline in Alaska, U.S. President Donald Trump said on Tuesday, claiming they would invest "trillions of dollars each.

Different versions of the Alaska LNG project have been discussed in Alaska for decades, and there are longstanding questions about how it would pencil out.

Some officials in South Korea say agreeing to the pipeline investment might placate the U.S., but Trump is still threatening tariffs.

South Korea and the United States have agreed to establish a working-level group to discuss a gas pipeline project in Alaska, energy, shipbuilding, tariffs and non-tariff barriers, South Korea's Industry Minister Ahn Duk-geun said on Tuesday.

Alaska political leaders on Wednesday broadly welcomed President Donald Trump’s remarks to Congress talking up the prospects of the state’s long-sought but faltering natural gas pipeline. In his speech to a joint session of Congress on Tuesday night,