U.S. Steel shareholders on Friday approved its proposed $14.9 billion acquisition by Japan's Nippon Steel, taking the merger one step closer to completion even as political opposition to the deal mounts.

U.S. Steel said that over 98% of the votes were in favor of the deal under which Nippon will pay $55 per share, an amount that represented a hefty premium when the takeover was announced in December.

Since then, however, several U.S. lawmakers have come out in opposition to the deal, citing national security concerns. President Joe Biden has said U.S. Steel must remain a domestically owned American firm.