The mayor of the town of Ayutla in the Mexican state of Jalisco has been shot dead by unidentified gunmen.

The motive for the killing is not yet clear, but police said they suspected a criminal gang to be behind it.

A little more than a month ago, the deputy police chief of Ayutla was also killed. No-one has been arrested for the killing so far.

Ayutla is a small town located in the Sierra Madre mountains in Jalisco state.

The state is the stronghold of the Jalisco New Generation cartel, which runs much of the large-scale drug trafficking along Mexico’s Pacific Coast.

The Mexican Local Government Association has urged the authorities to investigate the case, which it says is one of more than 50 unsolved murders of local leaders in the past seven years.

According to figures (in Spanish) released in July by Mexico’s National Institute of Federal Statistics, there were almost 3,500 fewer murders in 2013 than in 2012.

But some analysts have suggested that this may be down to the fact that relatives prefer to falsely register their loved ones’ deaths as due to natural causes.

Mexico’s murder rate peaked in 2011, when 27,213 people were killed, many of them in drug-related violence.