Updated

Mexico's main leftist party has pulled out of the Pact for Mexico, the multiparty alliance that has managed to push a range of reform programs through congress.

The Democratic Revolution Party's leader says his group walked out of talks on changing electoral law and overhauling the energy industry.

Jesus Zambrano says the Institutional Revolutionary Party of President Enrique Pena Nieto hasn't acted on the left's demands for a powerful central federal election board and for citizen involvement via ballot initiatives and other measures.

Zambrano also claimed Thursday that the president's party has been negotiating in secret with the conservative National Action Party to open the state-owned oil industry to wide-ranging private investment.

Zambrano said Democratic Revolution will return to the pact only if the ruling party changes its attitude.