MEXICO CITY – Mexico’s Institutional Revolutionary Party (PRI) has ended its alliance with the New Alliance Party (PANAL), PRI leader Pedro Joaquin Coldwell said.

The PRI and PANAL forged their alliance late last year in preparation for the July 2012 general elections.

“It’s not a rupture, it’s a friendly separation just because of the internal dynamics of the parties and we have decided to each go our own way to deal with electoral political interests,” Coldwell said during an interview with Televisa.

The PRI joined with the Mexican Green Party and PANAL in November to form the Compromiso por Mexico coalition.

The PRI, which governed Mexico from 1929 to 2000, is trying to regain the presidency after two straight losses to the conservative National Action Party, or PAN.

Polls show PRI candidate Enrique Peña Nieto as the favorite to win the July 1, 2012, presidential election and succeed President Felipe Calderon.

The PRI had agreed to back four senatorial candidates and 24 Chamber of Deputies candidates from the PANAL, a party founded by SNTE teachers union leader Elba Esther Gordillo.

Some of the PANAL candidates being supported by the PRI were relatives of Gordillo.

The PRI will continue its alliance with the Green Party and will back joint candidacies, Coldwell said.

The alliance was formed in light of electoral interests, but party leaders later evaluated the situation and decided it would be best for “everybody to go their own way,” Coldwell said.

Senatorial candidates will be registered on Sunday and candidates for seats in the lower house of Congress will be registered on Jan. 27, the PRI leader said.

The decision to part ways was made jointly and it is better for the PANAL to “go it alone,” PANAL leader Luis Castro Obregon said.

Former Mexico City Mayor Andres Manuel Lopez Obrador will be the candidate of the Progressive Movement alliance formed by the leftist Party of the Democratic Revolution, or PRD, the Workers Party, or PT, and the Movimiento Ciudadano.

The conservative National Action Party, or PAN, which is going it alone in the election, has not decided on a candidate yet.

Josefina Vazquez Mota, Santiago Creel and Ernesto Cordero have met all the requirements to compete for the PAN’s nomination, the National Elections Commission, or CNE, said.

Some 80 million Mexicans will be eligible to vote for a new president, 628 legislators and thousands of other officials in the general elections.