Celtic fans attacked by masked Ajax supporters NINE Ajax fans have been arrested after a group of Celtic fans were attacked at a bar in Amsterdam, ahead of the two teams meeting in the Champions League tonight. The incident is said to have occurred at the Old Sailor Cafe, in the city's "red light district," where a group of Celtic fans were attacked by a number of masked Ajax supporters shouting "Amsterdam hooligans." Local media reported that around 50 Celtic fans were in the pub at the time of the attack, with Amsterdam police later escorting the supporters from the area following the attack. Witnesses reported a fight breaking out before the Dutch fans left and security staff barricaded the bar's doors. Celtic fans drinking in the bar had earlier been interviewed by a local TV station ahead of the match at the Amsterdam ArenA this evening. It is believed the hooligans targeted the pub knowing Celtic fans would be inside. Celtic issued a warning on their official website, warning fans to be vigilant. The statement read: Celtic Football Club is urging all supporters in Amsterdam for tonight's UEFA Champions League tie with Ajax to be extra vigilant following an unprovoked attack on Celtic fans last night. The attack in the city-centre by an element of the Ajax support resulted in a number of arrests. Celtic are urging all supporters to be extra vigilant in the city-centre and at the Amsterdam ArenA, and to only stick to the advised areas for safety reasons. Meanwhile, the Dutch club could face UEFA sanctions following the behaviour of some supporters during the match at Celtic Park last month. Ajax fans clashed with stewards after Celtic's first goal in the 2-1 victory, tearing out seats and throwing them into the home support. European football's governing body are due to deal with the case later this month.