The US State Department on Sunday urged American citizens in parts of Mexico to shelter in place amid violence, road blocks and flight cancellations after Mexican soldiers killed a top cartel boss.

"Due to ongoing, widespread security operations and related road blockages and criminal activity in many areas of Mexico, US citizens should shelter in place until further notice," said a statement from the department's Consular Affairs section on social media platform X.

"Roadblocks have impacted airline operations, with some domestic and international flights canceled in both Guadalajara and Puerto Vallarta," it said.

Nemesio Oseguera, the 59-year-old leader of the Jalisco New Generation Cartel, was wounded in a clash with soldiers in the town of Tapalpa and died while being flown to Mexico City, the army said in a statement. He had a $15 million US bounty on his head.

Canada said it was monitoring the situation closely and advised Canadians in Mexico to "keep a low profile and follow advice of local authorities."

It urged citizens in Michoacan, Guerrero and Jalisco states to shelter in place, citing "shootouts with security forces and explosions."

Several US and Canadian airlines cancelled flights to parts of Mexico on Sunday following the unrest.

US carriers United, American, Southwest and Alaska, as well as the Canadian airlines Air Canada and WestJet/Sunwing, announced the cancellation of flights to Puerto Vallarta, Guadalajara, and Manzanillo.

Some planes had to turn back while already en route to Mexico, several airlines said, including Southwest, which turned back four flights originally bound for Puerto Vallarta.

Southwest said it would send aircraft to Mexico to repatriate its stranded passengers and staff once the situation normalizes.