An activist fighting against plans to build a gas pipeline through a town in Mexico was shot dead three days before a public vote on the project was due to take place.

Samir Flores Soberanes, 30, who was also a community radio producer, was gunned down on his doorstep in central Morelos around 5am on Wednesday.

The state government said a murder investigation was underway, and that so far there is “no indication that the murder is related” to an upcoming referendum on the Morelos Comprehensive Project.

However the environmental group The People’s Front in Defence of the Land and Water for the states of Morelos, Puebla and Tlaxcala (FPDTA), to which Mr Flores belonged, suspects the two events are connected.

Local communities have spent years fighting against the project which could see two thermoelectric plants, a gas pipeline to supply the plant with natural gas from Tlaxcala state, and an aqueduct built.

Trump shuts down US government over Mexico border wall – in pictures Show all 15 1 /15 Trump shuts down US government over Mexico border wall – in pictures Trump shuts down US government over Mexico border wall – in pictures Federal workers and contractors rally against the partial federal government shutdown Getty Images Trump shuts down US government over Mexico border wall – in pictures The US Capitol on the first morning of a partial government shutdown in Washington EPA Trump shuts down US government over Mexico border wall – in pictures Federal workers and contractors rally against the partial federal government shutdown Getty Trump shuts down US government over Mexico border wall – in pictures President Trump speaks with children who called the North American Aerospace Defense Command Santa tracker in the State Dining Room of the White House. He earlier in the day, tweeted that he was 'all alone in the White House' waiting for Democrats to make a deal on border security EPA Trump shuts down US government over Mexico border wall – in pictures Furloughed federal workers pick up free food at a pop-up store of Kraft Heinz Getty Images Trump shuts down US government over Mexico border wall – in pictures Hundreds of federal workers and contractors rally against the partial federal government shutdown Getty Trump shuts down US government over Mexico border wall – in pictures A pedestrian walk past the U.S. Capitol ahead of a possible partial government shut down in Washington, U.S., December 20, 2018. REUTERS/Joshua Roberts JOSHUA ROBERTS Reuters Trump shuts down US government over Mexico border wall – in pictures From left, House Majority Leader Steny Hoyer, Senate Minority Leader Chuck Schumer, Sen. Dick Durbin and Speaker of the House Nancy Pelosi walk to speak to reporters after meeting with President Donald Trump about border security in the Situation Room of the White House. Trump declared he could keep parts of the government shut down for "months or even years" as he and Democratic leaders failed in a second closed-door meeting to resolve his demand for billions of dollars for a border wall with Mexico Evan Vucci AP Trump shuts down US government over Mexico border wall – in pictures Federal workers and contractors rally against the partial federal government shutdown Getty Images Trump shuts down US government over Mexico border wall – in pictures A sign alerts visitors to the closure of the National Archives on the fifth day of a partial government shutdown EPA Trump shuts down US government over Mexico border wall – in pictures Hundreds of federal workers and contractors rally against the partial federal government shutdown Getty Images Trump shuts down US government over Mexico border wall – in pictures Visitors read signs announcing the closure of the White House Visitor Center EPA Trump shuts down US government over Mexico border wall – in pictures President Donald Trump speaks during a round-table discussion on border security and safe communities with State, local, and community leaders in the Cabinet Room of the White House Getty Images Trump shuts down US government over Mexico border wall – in pictures A sign alerts visitors to the closure of the White House Visitor Center on the first day of a partial government shutdown EPA Trump shuts down US government over Mexico border wall – in pictures Furloughed federal workers show their IDs for entering a pop-up store of Kraft Heinz Getty Images

The mostly indigenous communities around the Popocatepetl volcano, including Mr Flores’ town of Amilcingo, fear it will affect their health, safety and water supply. Mexico’s national electric company is behind the project, which has been under consideration since at least 2011.

FPDTA said that a day before his death, Mr Flores had attended a public forum about the project and challenged government representatives’ statements. The group said Mr Flores had been threatened a number of times since 2012.

The activist group also claimed that on the day of his murder, two vehicles parked outside Mr Flores' home and the people inside called to the activist before shooting him on his doorstep when he came out.

The funeral procession of Samir Flores Soberanes, a Mexican activist gunned down outside his home on 20 February 2019 (REUTERS)

Following his death earlier this week, the organisation also said it had warned Mexico president Andres Manuel Lopez Obrador in a letter that pushing ahead with the referendum on the project could lead to violence in the area.

Mr Lopez Obrador condemned Mr Flores’ murder as “vile” and “cowardly” – but said the public vote would go ahead as planned.

“I’m very sorry about the murder,” he said. “The consultation we have to continue because it is a process that was already agreed to.”

Support free-thinking journalism and attend Independent events

The government confirmed Mr Flores was shot in the doorway to his home and later died at a nearby hospital.

Officials say a murder investigation is underway and that they knew of a high number of criminal groups operating in the area.

Mr Lopez Obrador has used referendums to let the public decide on other large projects in the past.

One conducted before he took office resulted in the cancellation of Mexico City’s new international airport.

Another gave a green light to the president’s preferred project, a “Maya train” that would connect the resorts of Cancun and Tulum with ruins in Palenque and other spots on the Yucatan Peninsula.