Gunmen have fired on a military helicopter in Mexico, killing three soldiers and forcing it to make an emergency landing, as deadly violence erupted across Jalisco state during a new operation to capture drug cartel leaders.

Twelve other people - 10 soldiers and two federal police officers - were also injured and three soldiers remained missing on Friday, according to a statement from the defence ministry.

The incident came shortly after suspected cartel members set vehicles on fire in the same state's capital of Guadalajara and other cities.

In a separate incident, a police officer was killed in one of the clashes around the state in the community of Autlan, about 250km southwest of Guadalajara.

Al Jazeera's Adam Raney, reporting from Guadalajara, said that the incidents were believed to be coordinated by a criminal organisation.

"The officials are saying they are going to fight back and win this war that has been going on for more than eight years now in Mexico," he said.

Aristoteles Sandoval, Jalisco's governor, said that the violence was a reaction to the federal government's Operation Jalisco, "an operation to get to the bottom of and to be able to arrest all the leaders of this cartel, of this organisation".

Sandoval did not name the cartel, but authorities have been locked in an increasingly bloody battle with the Jalisco New Generation cartel.

Fifteen people had been arrested and there were four armed confrontations, he said.

Seven deaths

Sandoval said there had been a total of seven deaths on Friday, but did not specify the circumstances or the victims. 

Gonzalo Sanchez, a Jalisco state spokesman, said on Twitter that the dead included three soldiers, who died in the helicopter incident, one state security officer, one civilian and two suspected criminals.

President Enrique Pena Nieto said through his Twitter account that he lamented the soldiers' deaths in the course of their work in Jalisco.

Our correspondent said that Jalisco was not always the centre of the confrontations between the cartels and the security forces, but recently the Jalisco New Generation had staged a number of attacks in the state.

"It seems to be standing up to the government and saying: 'Do your best because it is not enough. We are here to stay'," he said.

Source: Al Jazeera and agencies