Education Secretary Alfonso Lujambio has decided not to run for the nomination of the National Action Party, or PAN, for next year's presidential election, reducing the ruling party's field to four candidates.

"My own polls and others" indicated that my candidacy lacked "positive competitiveness in the internal political field," Lujambio said in a press conference on Monday.

The education secretary said he would support whomever the PAN, which has held the presidency since 2000, runs in the July 2012 elections.

Finance Secretary Ernesto Cordero, who analysts say has the backing of President Felipe Calderon, Congresswoman Josefina Vazquez Mota, Sen. Santiago Creel and Jalisco Gov. Emilio Gonzalez will battle it out for the PAN's nomination.

The PAN's Vicente Fox won the 2000 presidential election, ending 71 years of Institutional Revolutionary Party, or PRI, rule in Mexico.

Calderon won the 2006 presidential election, succeeding Fox as president.

Mexico's political parties are expected to have their candidates in place by January.

The PAN, PRI and Party of the Democratic Revolution, or PRD, are seen as having the best chances of mounting bids to win the election.