"The patent laws of the United States make no discrimination with respect to the citizenship of the inventor. Any inventor, regardless of his/her citizenship, may apply for a patent on the same basis as a U.S. citizen. There are, however, a number of particular points of special interest to applicants located in foreign countries"
Excerpted from General Information Concerning Patents print brochure, US Patent and Trademark Office
In terms of the PCT, you want to make sure that you don't have to do an initial application when you file in your country. (In my case, I was advised to file the PCT app concurrently, which subsequently gives me about 18 months to decide to undertake the expense of filing in specific regions.) You definitely want to consult with an attorney on this.
If you follow all of the procedures correctly, this should be sufficient to prevent cloning in PCT regions.