TAIPEI—Beijing flew armed forces plane close to Taiwan on a day that a senior American diplomat met with Taiwan’s president as aspect of a series of current U.S. moves to boost ties with the self-dominated island.

Undersecretary of State Keith Krach, the greatest-position State Division official to go to the island because Washington slash official ties with Taipei four decades ago, expressed U.S. assistance for further cooperation at a meal Friday evening hosted by President Tsai Ing-wen, her place of work stated.