MEXICO CITY — Two top aides of Mexico City Mayor Clara Brugada were shot dead after being ambushed by gunmen on a motorbike in a daytime attack in the city center on Tuesday.

The victims were the mayor’s private secretary, Ximena Guzmán, and an adviser to Brugada, José Muñoz, according to a statement from the city.

The assassinations have sent shockwaves through Mexico’s capital, widely regarded as an oasis of relative security in a country plagued by violence. Political violence has become common in many parts of Mexico, where scores of local political candidates have been assassinated in killings usually linked to drug cartels seeking to exert influence.

Initial reports indicated Guzmn had been driving to work and stopped on a busy avenue in downtown Mexico City to pick up her colleague, an official at the federal prosecutor’s office said.

Muñoz was approached by two gunmen on a motorbike who shot and killed him in the street. The attackers then fired at least four shots at Guzmán inside the vehicle, killing her.

Authorities have not yet given a motive for the attack although security experts say it appeared to be a hit carried out by organized crime.

Mexico City’s civil security office said that a motorbike had been seized not far from attack, as well as another vehicle in the Iztacalco neighborhood, while investigators were looking into ballistic and fingerprint evidence from the scene.

“I feel very sad for the loss of Ximena and Pepe (Jose), with whom for many years we shared dreams and struggles,” a noticeably distressed Brugada said.

She thanked Mexican President Claudia Sheinbaum and her cabinet for the support and cooperation they had provided since the attack. Sheinbaum is a former mayor of Mexico City.

“It is a deplorable incident and we are going to give all the support that the mayor may need,” Sheinbaum said.

Brugada added that there would be no impunity for those responsible for the killing. She was not in the car when the attack took place, a Mexico City government official told Reuters.

Photos in local media showed a black Audi with four bullet holes in the front window and a sheet covering what appeared to be one body, while another body was covered with a white sheet on the pavement.

Police patrols taped off the area so forensic specialists could examine the scene.

“It was a harsh message sent to Clara (Brugada), undoubtedly perpetrated by drug traffickers,” said David Saucedo, a public security specialist. Groups affected by drug seizures have previously launched attacks against the capital’s authorities, he said.

In 2020 then Mexico City police chief Omar García Harfuch, now the federal security minister, was shot and injured in an assassination attempt that killed two of his bodyguards. That attack was blamed by him on one of the country’s most powerful drug groups, the Jalisco New Generation Cartel.