MEXICO CITY (Reuters) - Mexican leftist presidential candidate Andres Manuel Lopez Obrador retains a double-digit lead in the race to win the July 1 election but his second-place rival has slightly closed the gap, a poll showed on Wednesday.

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The poll was the first conducted by newspaper Reforma since an April 22 televised presidential debate, when the trailing pack of candidates launched sustained attacks on Lopez Obrador, putting him on the defensive.

The April 26-30 voter poll showed Lopez Obrador winning 48 percent support, unchanged from a Reforma voter survey earlier in April.

His nearest rival, Ricardo Anaya, who heads a right-left coalition, gained four points to 30 percent support. Jose Antonio Meade, candidate of the ruling Institutional Revolutionary Party remained in third place. His backing slipped one point to 17 percent, the poll showed.

Lopez Obrador vows to reduce inequality without raising taxes or debt, and he is likely to slow an economic liberalization program promoted by the current government. His government could also be more combative with U.S. President Donald Trump.

Trump’s claims that Mexican illegal immigrants are rapists and criminals and his complaints that Mexico has taken advantage of the United States over trade have made him unpopular south of the border.

The figures for the three candidates stripped out the 18 percent of respondents who expressed no preference. The poll surveyed 1,200 voters and had a margin of error of 3.6 percentage points.

In his third consecutive bid to reach the presidency, Lopez Obrador, a 64-year-old former mayor of Mexico City, has capitalized on widespread disenchantment with the PRI over political corruption, rising levels of violence and sluggish economic growth.

The survey showed Margarita Zavala, wife of former President Felipe Calderon, slipping to 3 percent from 5 percent previously.

The former governor of the state of Nuevo Leon, Jaime Rodriguez Calderon, who shocked Mexicans when he suggested during the presidential debate that thieves should have their hands chopped off, dropped 1 point and now just has 2 percent.

Still, only 9 percent said the debate had changed their mind regarding who they planned to vote for.

The debate was watched by 55 percent of those surveyed.

The survey also showed Lopez Obrador comfortably beating his two main rivals in direct head-to-head contests, though by smaller margins than in the prior poll.

Facing Anaya, he wins by a margin of 48 percent to 33 percent, and against Meade, by 52 percent to 24 percent.