KEY POINTS
  • "It is very hard for the Fed right now to go back to three hikes," economist Mohamed El-Erian says.
  • President Trump has repeatedly expressed frustration with the Fed, saying Monday it's a "much bigger problem than China."

The Federal Reserve next month will be forced to hike interest rates for a fourth time in 2018 or risk being seen as politically coerced, economist Mohamed El-Erian told CNBC on Tuesday.

"It is very hard for the Fed right now to go back to three hikes," the chief economic advisor at Allianz said on "Squawk Box." "If they don't [hike], the market is going to say the economy is much weaker than we anticipated and/or the Fed is much more open to political intervention."