A narco boat has deliberately rammed a Spanish customs patrol vessel during a dramatic high-speed chase off the coast of Almeria.

Authorities fear the incident could mark a dangerous escalation in the violence used by drug trafficking gangs operating in southern Spain.

The incident happened late on Thursday night when officers from the Customs Surveillance Service (SVA) attempted to intercept a suspected drug-smuggling vessel at sea.

According to sources from the Spanish Tax Agency, the patrol boat Audaz was pursuing one narcolancha at high speed when five additional drug boats suddenly appeared to protect it.

The customs vessel reportedly found itself surrounded by six large narco boats measuring between 18 and 25 metres long.

Sources close to the investigation say the smugglers used aggressive manoeuvres to obstruct the patrol boat before one of the vessels deliberately smashed into the side of the Audaz.

The impact shattered one of the port-side windows of the official vessel, sending glass flying towards the pilot inside the cabin.

Despite the violence of the collision, no officers were injured, although the patrol boat suffered material damage.

Authorities say the incident represents a worrying tactical shift among narco gangs.

Until now, traffickers typically attempted to block police pursuits by swarming around patrol boats or cutting across their paths to help escape vessels flee.

But directly ramming law enforcement boats has been far less common in anti-drug operations around Andalucia.

The attack comes just one week after two Guardia Civil officers died during a separate narco boat pursuit off the coast of Huelva when their vessel collided with another patrol craft during the operation.

The damaged vessel, Audaz, is one of the newest and fastest patrol boats operated by the Customs Surveillance Service.

Built this year by Spanish shipbuilder Rodman, the R-55 class boat is capable of reaching speeds of up to 67 knots and is specifically designed for high-speed anti-smuggling operations.

Read more Andalucia news at the Spanish Eye.