Mumbai, May 15 -- The Japanese yen weakened toward 158.5 per dollar on Friday, heading for a weekly decline of over 1% as intensifying US inflation pressures bolstered expectations of another Federal Reserve rate hike later this year. A surge in energy and trade costs linked to the Iran war continued to underpin the US dollar, with the dollar index climbing near 99 and poised for a solid weekly gain. Investor sentiment also remained cautious as markets monitored high-stakes discussions between President Donald Trump and Chinese President Xi Jinping, after Xi warned that Taiwan could emerge as a major flashpoint between the world's two largest economies. Adding to the hawkish undertone, Bank of Japan board member Kazuyuki Masu signaled sup...