Mexico's most wanted man and the leader of the feared Jalisco New Generation (CJNG) drug cartel has been killed during a security operation to arrest him, the country's defence ministry has said.

Nemesio Oseguera Cervantes, known as "El Mencho", died as he was being transported to the capital, Mexico City, after being seriously injured in clashes between his supporters and the army, the ministry said in a statement.

Four CJNG members were killed and another two seriously injured in the operation in the town of Tapalpa, in the central-western state of Jalisco. Three members of the military were also injured.

CJNG has spread from its original power base in Jalisco to have an almost nationwide presence across Mexico.

El Mencho, a former police officer, ran a vast criminal organisation responsible for trafficking huge quantities of cocaine, methamphetamine and fentanyl into the US.

It had offered a $15m (£11.1m) reward for information leading to El Mencho's capture.

The Mexican defence ministry said the US had supplied Mexico with information that assisted its operation.

It also said that several armoured vehicles and weapons - including rocket launchers - were seized during the operation.

The reaction from El Mencho's cartel has been immediate and violent.

In as many as eight different Mexican states, the group has set cars alight, set up roadblocks and attacked security forces.

Eyewitnesses have filmed plumes of smoke rising over several cities including Guadalajara - one of the host cities of th the forthcoming Fifa World Cup.

In the tourist hotspot of Puerto Vallarta, on the Jalisco coast, potentially thousands of tourists are trapped in the resort around the fighting.

Throughout Sunday, there were reports of gunmen on the streets in Jalisco and elsewhere.

The governor of Jalisco, Pablo Lemus Navarro, on social media advised residents of the state to adhere to a code red warning and avoid leaving their homes.

He also said that public transport was suspended in the state.

The US State Department issued a shelter-in-place warning for US citizens in Jalisco State, Tamaulipas State, and areas of Michoacan State, Guerrero State, and Nuevo Leon State.

Former US ambassador to Mexico and Deputy Secretary of State Christopher Landau described El Mencho on social media as "one of the bloodiest and most ruthless drug kingpins."

He added that El Mencho's death was "a great development for Mexico, the US, Latin America, and the world".

The killing of El Mencho represents a victory for Mexcio's President Claudia Sheinbaum Pardo in her fight against the country's drug cartels.

It also could strengthen her relationship with US President Trump, who often has demanded more progress on security in Mexico.

However, if the security forces can't bring the situation under control quickly, the Mexican administration's victory may be overshadowed by the cartel's violent response.

The Jalisco cartel has gained notoriety since it was formed in about 2010 for a series of attacks on security forces and public officials.

It has downed an army helicopter with a rocket-propelled grenade, killed dozens of state officials, and has even been known to hang the bodies of its victims from bridges to intimidate its rivals.