Obama Yellen propose to Fed Vice Chairman: source

WASHINGTON (Reuters) - U.S. President, Barack Obama plans to nominate the president of the Federal Reserve Bank of San Francisco, Janet Yellen, vice president of the country's central bank on Thursday said a source with knowledge of the process.

Yellen, considered one of the more moderate policy makers of the Fed, would replace Donald Kohn, who announced earlier that month eset retiring at the end of June. The nomination must be approved by the Senate.

Kohn's departure means he has to fill three seats on the board of seven members of the U.S. central bank. The source said the leading candidates for each office had been identified, but all the elect, including Yellen, are subject to a screening process.

The source said the government would also investigate several other candidates in case of cualquierda chosen is not approved.

When asked to comment on reports that Yellen was being considered for vice president, spokeswoman for the San Francisco Fed, Lily Ruiz, said: "We are not responding to any rumor or speculation."

(Reporting by Mark Felsenthal)