Police were called to reports of 30 men wearing balaclavas attacking a club in Leeds on Friday evening.
Officers were called to Rowland Road Social Club in Beeston after reports of a firework hitting the club, followed by '20 to 30 youths wearing balaclavas' turning up to attack it.
An apparent description of the incident circulating on social media today says: "Tonight while we were hosting a birthday party the club came under attack, firstly a 320 shot firework launched at patio. After ringing 101, I was given a reference number and told to ring 999 if they came back.
"20 minutes later around 30 all wearing balaclavas again attacked the club with sticks and stones, smashing the door window.
"Rang 999 at 10.40 and the guy could hear us under attack, was told to lock doors and not let anyone out and they were on their way.
"Now 12.15 and I had to allow people to go home"
West Yorkshire Police did not attend on Friday night.
Officers attended at 12.40pm on Saturday and recorded a crime of damage.