MEXICO CITY (AP) — Mexico’s old ruling party fractured Monday, with four leading senators resigning amid internal disputes and the loss of the last major state the party governed.

The Institutional Revolutionary Parties held the presidency and almost all statehouses in Mexico without interruption for 70 years.

But the PRI, as the party is known, has been reduced to a shadow of its former self by the rise of President Andrés Manuel López Obrador's Morena party, which won the governorship of the last major PRI bastion, the State of Mexico, last month.

Morena has seized on the combination of handout programs and nationalism that the PRI once espoused, and has largely replaced it.

On Monday, four leading PRI senators and dozens of supporters announced they are quitting the party. Senators led by former interior secretary Miguel Osorio Chong announced they will form a new group called “Congruence for Mexico.” The new group will not be able to compete in the 2024 presidential elections.

The PRI, which now governs only two sparsely populated states, is now Mexico's fourth biggest party, trailing Morena, the conservative National Action Party and the centrist Citizen's Movement.

Chong and the other senators had objected to attempts by current PRI party leader Alejandro Moreno to hold onto power.