China’s Foreign Ministry said on Tuesday it has expressed deep concern to the United States after Washington sent two warships through the Taiwan Strait. That was the second such operation this year. The latest operation shows the US Navy is increasing the pace of strait passages. Ministry spokeswoman Hua Chunying made the statement at a news briefing in Beijing. Taiwan’s Defense Ministry said it closely monitored the operation and was able to “maintain the security of the seas and the airspace” as it occurred, Reuters reported.