Federal Reserve Chairman Jerome Powell said the central bank is watching current economic developments and will do what it must to keep the near-record expansion going.

Financial markets have been nervous lately over an escalating trade war that has spread from China and now could include Mexico. At the same, government bond yields are behaving in a way that in the past has been a reliable recession indicator.

Powell began a speech Tuesday in Chicago by addressing "recent developments involving trade negotiations and other matters."

"We do not know how or when these issues will be resolved," he said in prepared remarks. "We are closely monitoring the implications of these developments for the U.S. economic outlook and, as always, we will act as appropriate to sustain the expansion, with a strong labor market and inflation near our symmetric 2 percent objective."

Powell's comments came at the "Conference on Monetary Strategy, Tools and Communications Practices," a kickoff for an examination the Fed is conducting this year about the tools it has to meet its goals as well as the way it is communicating its actions to the public.

He did not address any other specific issues relating to current conditions. Market are broadly expecting the policymaking Federal Open Market Committee to cut its benchmark rate twice before the end of the year in response to current conditions.

For his part, Powell has stuck to the position that the Fed remains data dependent. The most recent FOMC statement, from its May meeting, indicated that the committee is taking a patient stance toward policy changes at conditions evolve.