CATCo Share News (CAT)

* Futures down: Dow 257 pts, S&P 20.75 pts, Nasdaq 40.75 pts

By Sruthi Shankar

March 7 (Reuters) - U.S. stock index futures fell sharply onWednesday after the resignation of top economic adviser GaryCohn, a supporter of free trade in the White House, triggeredworries that President Donald Trump may push ahead with plans toimpose hefty metal tariffs and ignite a global trade war.

Dow e-minis were down 257 points by 7:20 a.m. ET.

Manufacturing giants Boeing and Caterpillarslipped 2 percent in premarket trading, while General Electricdipped 1.4 percent after Deutsche Bank analysts warnedthat rising metal input costs could weigh on a deal for its railbusiness.

S&P 500 e-minis were down 20.75 points and Nasdaq 100e-minis fell 40.75 points.

The declines continued from Tuesday night after Cohn, thearchitect of the tax overhaul enacted in December, said he wouldresign, a move that came after he lost a fight over Trump'splans for hefty steel and aluminum import tariffs.

Cohn, a former president and chief operating officer ofinvestment bank Goldman Sachs, was seen by investors as astabilizing force within the Trump administration.

Demand for safe-haven assets including U.S. government debtand Japanese yen rose, while Wall Street's fear gauge, the CBOEVolatility index, was up 11 percent at 20.42.

The ADP's National Employment Report, due at 8:15 a.m. ET,is expected to show private employers added 195,000 jobs inFebruary, compared with 234,000 jobs in January.

A more comprehensive report that includes hiring in bothpublic and private sectors is due on Friday.

The Federal Reserve will publish its Beige Book, acompendium of anecdotes on the health of the economy, in theafternoon. The Fed's next policy meeting is scheduled for March20-21.

Fed's New York President William Dudley and Atlanta Fedchief Raphael Bostic are expected to speak on Wednesday.(Reporting by Sruthi Shankar in Bengaluru; Editing by SrirajKalluvila)