Mexican President Enrique Pena Nieto on Saturday endorsed a change to the Institutional Revolutionary Party's rules that allows outsiders to run for president, a move that gives the embattled leader greater power to anoint his successor.

Gathering for their national assembly ahead of the 2018 election, members of the ruling PRI voted to relax requirements for presidential candidates, jettisoning a rule that nominees must be party members with at least 10 years' standing. The change opens the door to the candidacy of Pena Nieto's finance minister, Jose Antonio Meade, a soft-spoken technocrat who has served in various cabinet posts under both the PRI and the conservative National Action Party (PAN).

Pena Nieto made his way to the stage at a leisurely pace, spending 15 minutes greeting and posing for photographs with supporters in the crowd of more than 15,000 in Mexico City's Palacio de los Deportes. Sporting his trademark red track jacket, Pena Nieto echoed PRI leaders in describing the change as a move toward building a modern and more inclusive party.