The Irish police, Gardaí are investigating a significant fracas involving up to 20 men who tried to gatecrash a popular Dublin nightspot after the Longitude festival on Saturday.

Nigerian singer Naira Marley was scheduled to play at the nightspot, according to a report by Dublin Live. A number of other acts and DJs were also part of the line-up on the night.

The incident unfolded at Lost Lane just off Grafton Street before Marley took to the stage to perform.

“A video seen by Dublin Live shows up to 30 young men running out of the premises in the early hours of Sunday morning, with revellers of the adjoining pub looking on in confusion.

“The scene remained closed off to the public this morning, and gardai have since confirmed that a number of weapons have been seized and a man in his 20s arrested in connection with the incident”, Dublin Live reported.

An assortment of weapons including hatchets, knives and petrol bombs were found when the gang dispersed.

The incident occurred outside the Lost Lane venue, formerly Lillies Bordello, off Grafton Street in the south inner city shortly after 1am on Sunday.

Police believe the incident was connected with the Longitude Festival as a number of people who were at Longitude festival in Marlay Park, Rathfarham had gone to Lost Lane to continue socialising.

Gardaí further suspect the men who tried to rush the door of the venue had also been at the festival.

“Gardaí are treating the serious fracas as a spill over incident from Longitude. If the weapons found stashed around the Grafton Street area were linked to the men who tried to rush the door at Lost Lane, gardaí say that would confirm their suspicions the attempted gang attack was pre-planned”, the Irish Times reported.

Before the three-day Longitude festival began last Friday, the US Department of State Bureau of Consular Affairs tweeted a security alert about the event aimed at US citizens in Ireland.

“Reports indicate a potential for violence at the Longitude Festival taking place from July 5-7 in Marlay Park,” it said.

A security guard working at Lost Lane was injured and one man was arrested. However, gardaí believe significant violence was averted by the arrival of members of the force on the scene immediately as the trouble flared.