South Korea’s Ministry of Foreign Affairs (MOFA) said Tuesday it is reviewing whether to respond to an open letter from 54 Republican members of the U.S. House of Representatives urging Seoul to halt its investigation into Coupang, an e-commerce company at the center of a widening bilateral dispute.

The dispute is testing whether a domestic legal process can remain separate from alliance management as U.S. political and commercial pressure converges on a single corporate case.

MOFA spokesman Park Il saidofficials are “in consultations with relevant ministries regarding a response,” adding that the investigation is proceeding under domestic law without