BOSTON (AP) — Boston’s longest-serving mayor, Thomas Menino, says he does not plan to seek re-election for an unprecedented sixth term.

The popular Democratic mayor planned a formal announcement at 4 p.m. today.

He tells the Boston Herald and WBZ-FM that it was the toughest decision he has made in his life.

Menino was hospitalized for eight weeks in the fall after a respiratory infection and a blood clot that was complicated by a spinal fracture and diabetes, but told the Herald health issues played a “small portion” in his decision.

The 70-year-old Menino promises to go “full tilt” until his last day in office.

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