Taiwan will buy as many as 400 land-launched Harpoon missiles intended to repel a potential Chinese invasion, completing a deal that Congress approved in 2020, according to a trade group’s leader and people familiar with the issue.

Taiwan has previously purchased ship-launched versions of the Harpoon, which is made by Boeing. Now, a contract with Boeing issued on Taiwan’s behalf by the U.S. Naval Air Systems Command marks a first for the mobile, land-launched version, according to Rupert Hammond-Chambers, president of the U.S.-Taiwan Business Council. Three other people familiar with the deal, including an industry official, confirmed the contract is for Taiwan.

The Pentagon announced the $1.7 billion contract with Boeing on April 7 but made no mention of Taiwan as the purchaser. The deal comes as U.S.-China tensions are high, particularly over Taiwan, the self-governed island that China claims as part of its territory. China held military drills around Taiwan after its president met in California this month with U.S. House Speaker Kevin McCarthy.