She was the first woman to be elected to the post.
Widespread violence against politicians has overshadowed Mexico's general election, which saw two women run for the presidency.
Gunmen have killed the female mayor of a town in Mexico just hours after the country celebrated the election of Claudia Sheinbaum as the nation's first woman president.
Yolanda Sánchez was shot in the town of Cotija, which she had governed since September 2021.
She was the first woman to be elected to the post.
Widespread violence against politicians has overshadowed Mexico's general election, which saw two women run for the presidency.
Yolanda Sánchez was ambushed by gunmen in the centre of Cotija, Michoacán, on Monday.
Local media say she was shot 19 times and died in hospital shortly after the attack. Her bodyguard was also killed in the gun battle.
No arrests have been made so far in connection with the attack but it is widely thought that the gunmen belonged to an organised crime group.
Ms Sánchez had reported receiving death threats after taking up office in September 2021.
She was held for three days by armed men who had seized her at gunpoint during a visit to the neighbouring state of Jalisco in 2023. The politician said that her kidnappers had made "demands" and inflicted "psychological terror" before releasing her.
While she said that she did not know what criminal group they belonged to, local newspapers said the most likely culprits where the Jalisco New Generation cartel (CJNG).
The CJNG engages in drug trafficking as well as kidnapping for ransom and extortion.
It is also infamous for targeting public officials who refuse to do its bidding.
Ms Sánchez had said that the men who had threatened her after she had taken office had demanded that she hand the security of the town over to state police officers in the pay of organised crime groups.
She refused and asked for the military to reinforce the town. The mayor was also provided with armed bodyguards after the incident.
Mexico's violent cartels will be one of the many challenges facing Ms Sheinbaum as president
Her murder on Monday came less than a day after a general election that was overshadowed by the murder of local candidates.
More than 20 people running for office have been killed since September according to official figures, but independent surveys have put the number closer to 40.
The presidential race was won by Claudia Sheinbaum, who will be sworn in on 1 October as the first woman to hold the top office in Mexico.
Ms Sheinbaum's defeated rival, Xóchitl Gálvez, has been critical of the violence which marred the campaign.
Ms Gálvez said that when she called Ms Sheinbaum on Monday, she told her that "I saw a Mexico with a lot of pain and violence. I wished that she could solve the severe problems our people have”.
While Ms Gálvez conceded defeat after Ms Sheinbaum's unassailable lead in the polls was announced, she has since described the campaign for the presidency as an "unequal competition against the entire state apparatus dedicated to favouring its candidate".
She also said that she would challenge Ms Sheinbaum's win without specifying how she would do that.
With more than 95% of the votes tallied in the preliminary count, Ms Sheinbaum had a lead of over 31 percentage points over Ms Gálvez.