Okla. Stat. tit. 21 § 99
The term "peace officer" means any sheriff, police officer, federal law enforcement officer, tribal law enforcement officer, or any other law enforcement officer whose duty it is to enforce and preserve the public peace.
Every United States Marshal, Marshals Service deputy or other federal law enforcement officer who is employed full-time as a law enforcement officer by the federal government or is otherwise acting under the authority of a Federal Bureau of Indian Affairs Commission and has been certified by the Council on Law Enforcement Education and Training, who is authorized by federal law to conduct any investigation of, and make any arrest for, any offense in violation of federal law shall have the same authority, and be empowered to act, as peace officers within the State of Oklahoma in rendering assistance to any law enforcement officer in an emergency, or at the request of any officer, and to arrest any person committing any offense in violation of the laws of this state.
Okla. Stat. tit. 21, § 99