Can US customers use Kraken?

Could you please clarify if Kraken, a renowned cryptocurrency exchange platform, is accessible and operational for customers residing in the United States? I'm interested in knowing if there are any restrictions or limitations in place for US citizens looking to utilize their services for buying, selling, or trading digital currencies. Additionally, are there any specific regulations or compliance measures that Kraken adheres to in order to ensure a safe and secure trading environment for US-based clients?