The Progressive Movement, a new group within the leftist Party of the Democratic Revolution, or PRD, is being launched with the goal of eventually gaining the party's leadership and winning the presidency, former Mexico City Mayor Marcelo Ebrard said.

Mexico's leftist political forces must work together to take on President Enrique Peña Nieto and the Institutional Revolutionary Party, or PRI, Ebrard said during the launch of his movement on Saturday.

Ebrard, who has admitted in some interviews that he would like to make a run for the presidency in 2018, said he would serve as chairman of the Progressive Movement and was aiming to eventually take over the PRD's national leadership.

The most important move at this juncture is to win agreement on tax and energy reforms, the former Mexico City mayor said.

If the PRI and the conservative National Action Party, or PAN, want wide-ranging energy industry reforms via constitutional changes, they will have to ask the people for approval since petroleum is the country's main asset, Ebrard said.

Participants at the Progressive Movement conference discussed holding referendums so citizens can indicate how they want lawmakers to vote on tax and energy reforms.

The former Mexico City mayor was joined at the gathering by top PRD leaders, including party chairman Jesus Zambrano, who welcomed the new movement.

Ebrard, who served as the capital's mayor from 2006 to 2012, ran for the PRD's presidential nomination for the July 1, 2012, election but lost out to another former Mexico City mayor, Andres Manuel Lopez Obrador. EFE