The yen weakened sharply to the upper 143 range versus the U.S. dollar in Tokyo on Friday, after remarks by the Bank of Japan chief fueled speculation that the central bank is unlikely to further raise interest rates this year. BOJ Governor Kazuo Ueda said the central bank still has time to assess whether it needs to raise interest rates further in a press conference after the bank left the policy rate unchanged. The yen was trading in the upper 141 level against the dollar before his press conference.