Officials confirmed the discovery of up to 45 bodies at clandestine burial sites in Mexico, with an estimated 30 cadavers found in one spot in the northern state of Sonora and 15 buried under the patio of a multi-family house on the outskirts of Guadalajara in Jalisco state.

The Sonora state prosecutor's office said in a statement Saturday that it had sent forensics experts to accompany a volunteer search group that helped discover what was estimated to be 27 sets of human remains in a field near the city of Cajeme. Late Sunday, the volunteer group, Guerreras Buscadoras (Warrior Searchers), said it had found three more sets of remains.

The group is comprised of mostly women who organize their own digging teams for missing relatives in the face of official inaction.

The state and federal police guard a crime scene in Colonia Lindavista, Tepic, Mexico. (AAP)

"The Warrior Searchers are not alone in their hope of finding their loved ones, the Sonora prosecutors' office is accompanying them," the office said.

Clandestine burial sites have often been used by drug cartels in Mexico to hide the bodies of executed rivals or kidnap victims. While hundreds of such sites date back to the 2010-2016 drug war, some are more recent.

Volunteer searchers often act on tips about where burial grounds are located and then walk through fields plunging rods into the earth to detect the telltale odor of decomposing bodies.

On Monday, prosecutors in Jalisco said they were led to the patio burial site in Zapopan, a suburb of Guadalajara, earlier this month by an anonymous tip that bodies might be buried there. Jalisco state prosecutor Gerardo Solis said that the process of finding the bodies of one woman and 14 men had taken more than a week and that the cadavers had apparently been buried weeks ago.

A woman paints the name of a victim of the Mexican drug war onto a body outline as part of a memorial for those killed. (AAP)

Solis said neighbors had reported that the property — a kind of low-income, multifamily dwelling known in Mexico as a "vecinidad," where people often live in single rooms — had been used as a site for drug sales.

Disputes between drug cartels frequently result in the killings of a large number of low-level drug dealers.

After declining some, homicides in Mexico have risen to higher levels than the previous peak year of 2011 and violence remains a serious problem.

On Sunday, in central Guanajuato state, the Red Cross chapter in the city of Salamanca briefly suspended operations after a gang dragged a wounded patient out of an ambulance at gunpoint.

The government of the state of Guanajuato said that state or local police will accompany Red Cross ambulances "on the high risk or high-impact calls" — presumably calls related to gunshot victims.

FILE - This Feb. 22, 2014 file photo shows Joaquin "El Chapo" Guzman, the head of Mexico's Sinaloa Cartel, being escorted to a helicopter in Mexico City following his capture in the beach resort town of Mazatlan. Newly unsealed documents in the U.S. case against the Mexican drug lord say that witnesses have described him having sex with minors. According to papers unsealed Friday, Feb. 1, 2019, one witness told authorities that Joaquin Guzman had him drug girls as young as 13 before Guzman had s (AP/AAP)

The Red Cross chapter for Guanajuato shuttered operations in the city of 270,000, which has been plagued by violence between fuel theft gangs due to its gasoline refinery, but later resumed ambulance service.

In a statement, the Mexican Red Cross said it "is an impartial and neutral institution before all conflicts and its purpose is to relieve human suffering," adding the "#We are not part of the conflict" hashtag.

Earlier this month, a woman with gunshot wounds was executed inside an ambulance in Mexico's Pacific state of Guerrero, and paramedics were reportedly beaten by the perpetrators.