Is Phemex legal in the US?

Could you please clarify for me if Phemex is legally operating within the United States? I've heard of it being a popular platform for cryptocurrency trading, but I'm unsure of its regulatory status in the country. It would be greatly appreciated if you could provide some insight into whether or not Phemex is authorized to operate in the US and if there are any potential legal implications for users who engage in transactions on the platform.