WASHINGTON (MarketWatch) - The timing of interest-rate increases and the unwinding of special lending programs will depend on economic conditions and financial developments, Federal Reserve Chairman Ben Bernanke testified Thursday. "In due course, as the expansion matures, the Federal Reserve will need to begin to tighten monetary conditions to prevent the development of inflationary pressures," Bernanke said in testimony to the House Financial Services Committee. For now, however, the economy remains so fragile that extremely low interest rates will be needed for an extended period, he said.