VILLA UNION, Mexico－Mexican forces hunted on Monday for drug cartel gunmen behind a bloody firefight in a town near the US border that left six locals and 16 gunmen dead－the latest security embarrassment for Mexican President Andres Manuel Lopez Obrador.

At least 60 gunmen terrorized the small northern city of Villa Union over the weekend, riding into town in heavily armed four-wheel drive vehicles and spraying dozens of houses with bullets before attacking city hall, taking seven hostages along the way, including five minors.

Mexican officials responded by deploying the army, the National Guard and police forces, triggering a series of firefights on Saturday and Sunday that left 22 people dead: Two kidnapped city employees and four state police officers were killed, aside from 16 gunmen, according to authorities in Coahuila state, where Villa Union is located.

Witnesses said the gunmen wore the insignia of the "Northeast Cartel", a breakaway from the ultra-violent Zetas, a drug cartel founded by corrupt army commandos in the northern state of Tamaulipas in 2010.

Authorities arrested two of the gunmen, who told investigators the cartel's objective was to "come in and hit Villa Union hard" in order to "intimidate" the state government, according to Governor Miguel Angel Riquelme.

Riquelme praised the "bravery" of the group of 15 police who responded to the initial attack, whom he said managed to contain the gunmen, even though they were badly outnumbered.

"Within an hour-and-a-half, we had the criminals surrounded," he told radio network Formula.

"Security forces are deployed on the ground and in the air across the region, to ensure this cowardly attack does not go unpunished," the state's emergency response agency said in a statement.

Latest disaster

The attack was the latest in a string of security disasters for Lopez Obrador's government since the leader took office a year ago promising a change in strategy against Mexico's powerful drug cartels.

His plan－summed up in his mantra "hugs not bullets"－is to attack violent crime at its roots by fighting poverty and inequality with social programs, rather than with the army.

But there are few signs that is working. Mexico appears on track to set a new murder record this year, with 28,741 so far.

Recent high-profile episodes have heightened the pressure on the government.

Last month, gunmen believed to be from the La Linea drug cartel massacred nine Mormon women and children with dual US-Mexican nationality in a remote area between the northern states of Sonora and Chihuahua.

And in October, authorities briefly arrested Ovidio Guzman, son of jailed kingpin Joaquin "El Chapo" Guzman, and then were forced to release him when gunmen from their Sinaloa cartel laid siege to the western city of Culiacan.

That incident appears to have "radiated" to other cartels, convincing them they can gain the upper hand with violent attacks, said security expert Raul Benitez of Mexico's largest university, UNAM.

"What happened in Villa Union is a reflection of what happened in Sinaloa," he said.