President Donald Trump has acknowledged that U.S. officials are communicating with Iran through mediators, even as tensions remain high between Washington and Tehran. The renewed contacts come after Iranian officials warned that the country is prepared for a “doomsday war” if hostilities resume. Reuters reports that U.S. and Iranian officials separately spoke with mediators as efforts to revive negotiations continued. Trump has rejected Iran’s latest proposal but said further talks are expected this week. The negotiations are focused on ending the conflict, sanctions, Iran’s nuclear programme and reopening the strategically vital Strait of Hormuz.