According to official data, Mexico this year has registered its highest murder total since modern records began, dealing a fresh blow to President Enrique Pena Nieto's pledge to get gang violence under control with presidential elections due next year.

A total of 23,101 murder investigations were opened in the first 11 months of this year, surpassing the 22,409 registered in the whole of 2011, figures published Friday night by the interior ministry showed. The figures go back to 1997.

Pena Nieto took office in December 2012 pledging to tame the violence that escalated under his predecessor, Felipe Calderon. He managed to reduce the murder tally during the first two years of his term, but since then it has risen steadily.