US intelligence believes Russia is behind the acoustic and directed energy attacks. The Washington Post writes about this with reference to unnamed representatives of the US intelligence community.

The newspaper recalled several cases of acoustic attacks on American diplomats, including incidents in Cuba. "Following reports of similar incidents in China, Russia and even the United States, US intelligence officials now claim that Russia is responsible for attacks that may employ microwaves or other forms of directed energy."

Politico, citing knowledgeable sources, reported that the US authorities suspect that the Russian GRU may be behind the alleged "directed energy" attacks against US diplomats and intelligence officers around the world. At the same time, the publication noted that so far there is no direct evidence of Russia's involvement in these attacks.

directed energy attack is the impact of highly concentrated electromagnetic energy, including the use of powerful radio frequency or microwave devices, as well as particle streams. Results can be very different.

Biggest fun here is that US totally made thing up. As they have only words of few people that they "felt something", no proof, no anything.
It is ideal thing to make accusations that no one have any slightest chance to debunk.