A new poll indicates that conservative Mexican presidential candidate Felipe Calderon holds a slim lead ahead of his nearest rival as the July 2 election approaches.

The survey shows that Calderon, the candidate of the ruling National Action Party (PAN) has 34.5 percent of voter support.

Andres Manuel Lopez Obrador, of the leftist Democratic Revolution Party (PRD), is a close second with 31.3 percent. Institutional Revolutionary Party (PRI) candidate Roberto Madrazo trails with just over 27 percent of the vote.

The survey, released Monday by polling firm Zogby International and the University of Miami, also shows that 13 percent of likely voters are still undecided.

Nearly 15-hundred people were surveyed for the poll, which had a margin of error of about three percent. Almost half of those surveyed (49 percent) said they believed Mexico was headed in the right direction.

In May, a similar survey by Zogby and the school put Calderon ahead of Lopez Obrador by five percentage points.

Last week, Mexico's El Universal newspaper published its own poll which also showed the two men in a close race.

The person who wins the election will replace President Vicente Fox, who by law cannot seek a second term. His 2000 victory ended 71 years of rule by the Institutional Revolutionary Party.

Some information for this report was provided by AP and Reuters.