U.S. Rep. Ed Pastor, a Democrat who is the senior member of Arizona's U.S. House delegation, has announced he will retire at the end of this current term.

Pastor says in a news release issued Thursday that it's time for him to "seek out a new endeavor."

His decision to not run for re-election is expected to set the stage for a contested Democratic primary in Arizona's 7th Congressional District. The heavily Hispanic District is located entirely in the Phoenix and leans Democratic in registration.

When he leaves office, Pastor will have served 23 years in Congress. He previously served as a Maricopa County Supervisor from 1976 to 1991.