See the USMLE website for details. However, earning only mbbs it's highly unlikely you will ever pass. Of the few foreign-trained doctors who ever take it & actually make it to Phase 3, less than half pass.
Then consider that there are no longer enough hospital residencies for American graduates of US medical schools. And they have MD, not just mbbs. Obummercare has devastated US medical system. Hospitals are laying off staff at every level from attendings to janitors. Forget it.
You are going to have to pass the medical exams in your country of citizenship. You neglect to mention, however, Ukraine is very popular with Indian students. You need to know, if you're Indian citizen, that 40% of Indians who earn mbbs in India fail India's medical exams; failure rate for Indians who study abroad is nearly double that rate. You MUST pass India's exams if you are Indian citizen (vast majority of those who pass India's exams, then try to take USMLE can't survive it), If you are a citizen of some other country, you must pass your country's exams.
BTW, just in case you are Indian, you also need to know that of Indian doctors who earned MD in the US & used to practice in US, over 19,000 of them have returned to India as of last September.