The Federal Reserve's decision Wednesday to raise the benchmark interest rate is a vote of "confidence" in the health of the US economy, Fed Chair Janet Yellen said.

The increase, which was widely anticipated by markets, "should certainly be understood as a reflection of the confidence we have in the progress that the economy has made and our judgment that progress will continue," Yellen told a press conference.

She also noted that any increased spending by the incoming Republican administration of President-elect Donald Trump could impact how the Fed adjusts interest rates going forward, but cautioned it was too soon to speculate.