FRANKFURT, May 21 (Reuters) - U.S. Treasury Secretary Janet Yellen said on Tuesday that the United States and Europe need to respond to China's industrial policies in a "strategic and united way" to keep manufacturers viable on both sides of the Atlantic.

In remarks on the importance of the U.S.-European alliance in Frankfurt, Yellen said China's excess industrial capacity threatens both American and European firms as well as the industrial development of emerging market countries.

"China’s industrial policy may seem remote as we sit here in this room, but if we do not respond strategically and in a united way, the viability of businesses in both our countries and around the world could be at risk," she said.

(Reporting by David Lawder; editing by Mark Heinrich)