The US state department has urged its staff in China to alert them to any abnormal hearing or vision issues after one employee reported mystery symptoms.

The person that experienced this had "subtle and vague, but abnormal, sensations of sound and pressure", a statement said.

Secretary of State Mike Pompeo said the incident was "medically similar" to suspected sonic attacks to ones on diplomatic staff in Cuba.

The state department said it was taking the incident "very seriously", but the US has not accused China of being behind it.

What happened in China?

Embassy spokeswoman Jinnie Lee said the employee had suffered a "variety of physical symptoms" between late 2017 and April 2018 while working in the city of Guangzhou.

The employee was sent back to the US, the embassy learnt that they had been diagnosed with mild traumatic brain injury (MTBI).

"We do not currently know what caused the reported symptoms and we are not aware of any similar situations in China, either inside or outside of the diplomatic community," the US diplomatic statement said.

"The US government is taking these reports seriously and has informed its official staff in China of this event," it added

The statement continues with a warning: "While in China, if you experience any unusual acute auditory or sensory phenomena accompanied by unusual sounds or piercing noises, do not attempt to locate their source. Instead, move to a location where the sounds are not present."

Was this a sonic attack?

Mr Pompeo told the House of Representatives Foreign Affairs Committee that the occurrences were "medically similar", adding that medical teams were on their way to Guangzhou to investigate.

However, there is nothing so far to link the China incident directly to Cuba. - "We cannot at this time connect it with what happened in Havana but we are investigating all possibilities," a US embassy official in Beijing told AFP news agency on condition of anonymity.

Types of sonic weapon

=
Infrasound - below 20Hz

At frequencies too low for humans to hear
If very loud can cause vertigo, vomiting or uncontrollable defecation
Would need huge racks of speakers to be effective

Ultrasound - above 20,000Hz

Easier to target
Possible to direct sound through walls
Risk of affecting people other than those targeted, including person carrying out attack

What happened in Cuba?

In November 2016, US diplomats based in Cuba started to complain of odd ailments, including dizziness, nausea and hearing problems.

More than 20 members of staff in Havana were harmed in the "health attacks", according to the state department. At least two Canadians were also affected.

The US has held Cuba responsible, either for allowing the suspected attacks to happen or for carrying them out itself.
Cuba has denied any involvement.

This is very interesting because we know it can be done as shown in Cuba, and especially with the strains between America and China over trade at the moment, this could be China getting its own back, or trying to force American diplomats out of the country. USA hasn't accused China to be behind this and will likely wait for more evidence before they make their move.

All information taken from this source

So guys what do you think?