Federal Reserve officials gave mixed signals on inflation ahead of Chairman Kevin Warsh's keynote at the central bank's annual conference, Bloomberg reported Thursday.

Kansas City Fed President Jeff Schmid and Cleveland Fed President Beth Hammack said rates are not restraining the economy enough and argued for further hikes to reach the 2% inflation goal, the report said.

"We've got work to do," Schmid told Bloomberg TV, while Hammack told CNBC that more restraint is needed, according to the report.

Boston Fed President Susan Collins countered that current policy is "mildly restrictive," while Chicago Fed President Austan Goolsbee said he is waiting for evidence inflation shocks are not persistent, Bloomberg reported.