Tottenham have vowed to take the “strongest possible action” after their 2-0 defeat by Chelsea was overshadowed by the game having to be paused when Antonio Rüdiger was targeted with racist abuse by a section of the crowd.

Anthony Taylor, the referee, stopped play during the second half when an object was thrown at Kepa Arrizabalaga, Chelsea’s goalkeeper, and Rüdiger told him he had suffered racist taunts. The German centre-back appeared to indicate a supporter had shouted a monkey chant at him and an announcement over the PA system at the Tottenham Hotspur Stadium told the crowd that “racist behaviour is interfering with the game”.

César Azipilicueta, the Chelsea captain, also brought the incident to Taylor’s attention, which took place moments after the Spurs forward Son Heung-min had been sent off following a clash with Rüdiger. Taylor asked for the announcement to be broadcast to the crowd and, though it was repeated twice, it is understood that only one allegation of racism was made. Uefa’s three‑step protocol says a game can be abandoned if fans have been warned twice before.

Spurs may not be charged by the Football Association over the racism, as it has no jurisdiction over individual fans, but are likely to be asked for observations over missiles thrown from the stands. The club said: “We are now conducting a thorough investigation which will include liaising with Chelsea and their players for their observations. Any form of racism is completely unacceptable and will not be tolerated in our stadium. We take any such allegations extremely seriously and shall take the strongest possible action against any individual found to be behaving in such a way, including stadium bans.”

Racism has blighted English football over the past 12 months. The Manchester derby was marred by a City fan appearing to make a monkey gesture at United’s Fred, while a League Two game between Scunthorpe and Forest Green Rovers was halted after allegations of racist abuse on the same day. An FA Cup tie between Haringey Borough and Yeovil this season was replayed following racist abuse from the crowd.

Rüdiger condemned the latest incident, writing on Twitter “#NoToRacism #PleaseGetSomeBasicEducation”. Late last night he wrote: “I don’t want to involve Tottenham as an entire club into this situation as I know that just a couple of idiots were the offenders. I got a lot of supportive messages on social media from Spurs fans as well in the last hours – thank you a lot for this.

“I really hope the offenders will be found and punished soon and in such a modern football ground with dozens of TV and security cameras, it must be possible”

José Mourinho, the Spurs manager, said he was saddened that racism has still not been eradicated from the game. “It’s something that upsets me,” Mourinho said. “I hate racism in society, hate racism in football. I am disappointed that things like that still can happen. But the referee stopped the game, spoke with the players, spoke with the captains, spoke with the coaches.

“I was losing, I don’t want the game to be stopped. But immediately when I knew the reason why the game was stopped, I obviously understood and accepted it. I think the club is a very proud club in this kind of situation and the club also internally will try to deal with it.”

Frank Lampard offered Rüdiger support and said: “I don’t know if it is getting better or worse or not. We are much more aware that we have a protocol to report it, which is a positive step. Of course, in a perfect world that protocol isn’t needed. If it is fact and true and it happened, then it needs to be dealt with and the punishment needs to be strong.”

The Professional Footballers’ Association called for a government inquiry into racism within football following the allegations in one of a series of tweets after the match.

The incident detracted from a wonderful performance from Chelsea, who remained in fourth place after going six points above Spurs. Lampard’s tactics worked magnificently and his side sealed a fine win thanks to two goals from Willian in the first half. The Brazilian’s second came after Paulo Gazzaniga, the Spurs goalkeeper, conceded a penalty with a wild foul on Marcos Alonso.

Mourinho sarcastically suggested Rüdiger had overreacted after being kicked by Son, who was sent off after a VAR review. “Rüdiger is having scans in the hospital on broken ribs, because it was really a violent situation,” the former Chelsea manager said. “In some countries, like mine, for example with our cultures, we used to say: ‘Clever player.’ But in this country, and one of reasons why I fell in love with this country in 2004 is because we don’t call them clever, we call them other things, that I refuse to call.”

Lampard brushed aside the criticism from his former manager. “It was a red card,” he said. “I don’t know how much he’s supposed to make out of it. Sometimes in football you have instinctive moments. It happened, it was a bit of a reflex. I will not have any words said about how Toni Rüdiger dealt with that.”