U.S. tariffs are an "evolving story" and it is too early to assess their impact on the world economy, International Monetary Fund Managing Director Kristalina Georgieva said Tuesday.

"It is an evolving story... What we have are elements of trade policy that we expected would come, that was announced in the election campaign, but there are many, many unknowns," she told the World Government Summit in Dubai.

"So when I think of the impact on the world economy, my answer to you would be today, it's too early to say."

Georgieva said the world economy appeared remarkably resilient, despite a series of unprecedented shocks.

The outlook for inflation was hard to predict, she suggested.

"Even on that, we just need to see how things evolve. Because if we are in the situation in which, in some parts of the world, there is a slowdown that may push central banks to bring interest rates down, that may actually not be inflationary."

U.S. President Donald Trump substantially raised tariffs on steel and aluminum imports on Monday to a flat 25%, a move he hopes will aid the struggling industries in the United States but which also risks sparking a multi-front trade war.