HAVANA — Raul Castro seemed rattled.

The Cuban president sent for the top American envoy in the country to address grave concerns about a spate of U.S. diplomats harmed in Havana. There was talk of futuristic “sonic attacks” and the subtle threat of repercussions by the United States, until recently Cuba’s sworn enemy.

The way Castro responded surprised Washington, several U.S. officials familiar with the exchange told The Associated Press.

In a rare face-to-face conversation, Castro told U.S. diplomat Jeffrey DeLaurentis that he was equally baffled, and concerned. Predictably, Castro denied any responsibility. But U.S. officials were caught off guard by the way he addressed the matter, devoid of the indignant, how-dare-you-accuse-us attitude the U.S. had come to expect from Cuba’s leaders.

The Cubans even offered to let the FBI come down to Havana to investigate. Though U.S.-Cuban cooperation has improved recently — there was a joint “law enforcement dialogue” Friday in Washington — this level of access was extraordinary.