Patrons at a Melbourne restaurant ran away in panic after a masked group attacked a gathering with machetes last night, leaving a teenager in hospital.

An 18-year-old boy was part of a large group seated outside Vanilla Lounge at Eaton Mall when 12 unknown offenders, a wearing balaclavas approached at about 7.45pm.

At least two of the masked group pulled out machetes and attacked the Malvern East man.

Patrons at a Melbourne restaurant ran away in panic after a masked group attacked a gathering with machetes last night, leaving a teenager in hospital.© Supplied

The man was kicked, punched and slashed in the face as he lay hapless on the ground.

The attack was caught on multiple CCTV cameras nearby, as well as on phone footage taken by bystanders.

One CCTV shows patrons at surrounding tables either fleeing in fear after the attack began, or hiding underneath tables.

The attack was caught on multiple CCTV cameras nearby, as well as on phone footage taken by bystanders.© 9News

“Everyone was so scared,” Kay Garg, who was dining at nearby Mythos Gyros Bar, said.

“Everyone was running to our restaurant.”

The 18-year-old was taken to hospital with serious but non-life-threatening injuries.

A 16-year-old boy was also attacked but was physically uninjured.

“The boy was sitting inside the Vanilla, everyone was putting hankies and all to cover his blood, there was a lot of blood,” Garg said.

One CCTV shows patrons at surrounding tables either fleeing in fear after the attack began, or hiding underneath tables.© Supplied

The attackers fled on foot and no arrests have been made.

Despite the offenders not yet being identified, police believe it was a targeted incident between parties known to one another.

Police said they would conduct proactive patrols in the area.

An 18-year-old boy was part of a large group seated outside Vanilla Lounge at Eaton Mall when 12 unknown offenders, a wearing balaclavas approached at about 7.45pm.© 9News