Taiwan is confident it can sign a trade deal with Washington, its leader told visiting US lawmakers Thursday, adding that the island "will not back down" against Chinese threats.

Washington unveiled plans for formal trade talks with Taiwan in a show of support as China was staging huge military drills last month.

Taiwan lives under constant threat of an invasion by China, which claims the democratically ruled island as part of its territory to be seized one day — by force if necessary.

Beijing lashes out at any diplomatic action that seems to treat Taiwan as a sovereign nation, and has reacted with growing anger to visits by Western politicians.

Last month's drills were in protest at US House Speaker Nancy Pelosi's visit to Taiwan.

While meeting the bipartisan US delegation, Taiwanese President Tsai Ing-wen pledged to work with Washington to promote closer trade ties.

"We are confident that through this initiative, we can sign a high-standard trade agreement and advance bilateral trade development," she said.

Representative Stephanie Murphy, a Democrat from Florida, urged Congress to "deepen economic relationship with Taiwan, in particular by pushing for a high quality Free Trade Agreement between the US and Taiwan".

China's unprecedented drills triggered widespread support in the United States for solidarity with Taiwan, which already has rare bipartisan support on Capitol Hill.

So far this year 28 members of Congress have traveled to Taiwan, the highest number since at least 2013, according to data from Bloomberg News.

Last week the US announced a $1.1 billion arms package for Taiwan, vowing to keep boosting the island's defenses.

Many European powers have also grown more vocal in support of Taiwan in recent years, while Russia invading Ukraine has deepened fears China might do the same to its neighbor.