Governor Silvano Aureoles distanced himself from his initial statement on Tuesday, in which he said criminals downed the helicopter in the troubled western state of Michoacan, killing four people.

Hours after writing on Twitter that the helicopter had been shot down by criminal elements, Aureoles said in a television interview that he couldn't confirm the reports yet.

"We are doing the investigations," he told Televisa network, according to AFP news agency.

The helicopter was on a mission to help arrest the leaders of criminal cells active in the area, which is known for its heavy bouts of gang-related violence.

Aureoles paid tribute to the victims of the crash on Twitter. "We lament the death of the pilot, three police officers and another wounded officer who were fulfilling their duty to uphold peace in the state," the governor wrote.

Hotbed of violence

The helicopter went down near Apatzingan, a city in a region called Tierra Caliente ("Hot Land"), where much of the state's violence occurs.

Last year, members of the Jalisco New Generation drug cartel used a rocket launcher to down a military helicopter. Six soldiers were killed.

Michoacan has one of the highest murder rates in all of Mexico. Members of the Knights Templar drug cartel lorded over much of Tierra Caliente until local lime growers turned vigilante in 2013 in order to fight back against them.

blc/jm (Reuters, AFP)