TOEFL or IELTS is not required for international students who have completed (or is about to complete) a degree program in an English speaking country such as UK, US, Australia, Canada. GRE is required for all candidates who apply for graduate programs at the US universities. Therefore, you do not need to take the language tests but must have a GRE score (unless you are applying for a MFA, or some programs about design, music, performance, drama etc.).