U.S. Federal Reserve chair Janet Yellen says she expects a rate hike to happen before the end of the year. Speaking at a news conference in Washington on Thursday, Yellen said inflation will gradually move up to the Fed′s target of two-percent once oil prices rise and the dollar weakens. This was Yellen′s first speech since the Fed voted last week to keep interest rates at their current record low of near-zero. She added that current global economic risks will not affect the central bank′s plans to raise its key rate by December. Yellen also said the central bank would need to tighten its policy in a timely fashion at a gradual pace.