Secretary of State Antony Blinken says he has warned Chinese leaders about "deep" US concerns regarding reports of sensitive operations by Beijing on Cuba. "Yes, I made very clear we would have deep concerns about PRC (People's Republic of China) intelligence or military activities in Cuba," the United States' top diplomat tells reporters in London after visiting Beijing. "This is something we're going to be monitoring very, very closely, and we've been very clear about that," he adds.