Gunmen killed six people at a party in northwestern Mexico on Friday, including an alleged criminal believed to have been targeted in the attack, authorities said.

"Initial investigations indicate that it was a direct attack against the leader of a criminal group who had arrest warrants for attempted femicide, homicide, illegal deprivation of liberty and criminal association," the Sonora state prosecutor's office said.

It said the unidentified target was killed along with five others, while 26 people were injured in the early morning attack in the municipality of Cajeme.

Prosecutors said they were unable to confirm reports that the gathering was a 15th birthday party.

Cartel gunmen have a history of targeting social gatherings in Mexico, where more than 420,000 people have been murdered in a spiral of drug-related violence since 2006.

On December 17, gunmen opened fire at a Christmas party attended by young Mexicans in the central state of Guanajuato, killing 11 people.