Federal Reserve Chair Janet Yellen's speech earlier on Friday was consistent with expectations for possible interest rate hikes this year, Fed Vice Chair Stanley Fischer said, reinforcing the message that the U.S. economy has strengthened.

Fischer was asked on CNBC whether people should "be on the edge of our seat" for a rate hike in September, and for more than one policy tightening before year end.

He answered: "I think what the Chair said today was consistent with answering yes to both of your questions, but these are not things we know until we see the data."

Hours earlier in Jackson Hole, Wyoming, Yellen said the case for "an increase" in the Fed's policy rate has strengthened in recent months due to improvements in the labor market and to expectations for solid economic growth.

Fischer, the Fed's No. 2 policymaker, said the Labor Department's jobs report for August will likely weigh on the decision over a hike. "I think the evidence is the economy has strengthened... (with) the big numbers are better than they have been for some time," he said of the economic data.

The Fed has policy meetings in September, November and December.