Masked gunmen burst into a children's party in central Mexico and killed 11 people, authorities and witnesses said Thursday, in the violence-plagued country's latest mass murder.

Police found the gory scene when they responded to an emergency call received just after midnight in the city of Tizayuca, in the central state of Hidalgo, the state security service said in a statement.

Neighbours said four gunmen burst into a large white tent where a family was hosting a children's party outside their home and shot dead seven men and four women.

Four children were found unharmed, public security spokesman David Pichardo told AFP.

One of the children told authorities that masked men wearing police uniforms had arrived during the party and killed all the adults, according to newspaper Excelsior.

Authorities had cordoned off the entire neighbourhood Thursday morning, and security was tight. Forensic workers could be seen examining the crime scene.

Mexico has seen a surge of deadly violence in recent months, extending to areas that were once considered relatively calm. That includes Hidalgo, which sits just north of the capital, Mexico City.

Murders hit a record high in May, according to the latest official data: 2,186 homicides, an average of 70 a day and the most since the country began keeping track 20 years ago.

The violence is fueled by powerful, ultra-violent drug cartels.

Since Mexico deployed the military to fight drug trafficking in 2006, a wave of bloodshed has left more than 200,000 people dead or missing, as rival cartels wage war on each other and the army.

Recently, hitmen have been wiping out entire families -- including children -- in a sign that the unspoken code of honour that once governed the turf wars and revenge killings of Mexico's cartels is fraying.