Chelsea defender Antonio Rüdiger demanded swift punishments for Tottenham fans who aimed monkey noises at him on Sunday during a London derby where the stadium announcer issued three warnings for the racism to stop in an unprecedented move for the Premier League.

“It's just such a shame that racism still exists in 2019,” Rüdiger tweeted. “When will this nonsense stop?”

The latest high-profile incident of racism at an English stadium led to calls from the players' union for a government inquiry to hasten the search for solutions along with the police and officials across soccer.

“It is really sad to see racism again at a football match, but I think it's very important to talk about it in public,” Rüdiger said. “If not, it will be forgotten again in a couple of days (as always).”

The announcements at Tottenham Hotspur Stadium were made at 10-minute intervals, starting midway through the second half of the game with Chelsea leading 2-0, which was the final result.

“Racist behavior among spectators is interfering with the game," the announcer announced in a warning to the crowd of 61,104. "Please remember in football there is no place for racism.”

The abuse reported by Rüdiger came after he was kicked in the chest by Tottenham forward Son Heung-min, who was sent off as a result.

Rüdiger, who is black, was seen putting his hands under his armpits - seemingly mimicking a monkey gesture - before informing captain Cesar Azpilicueta. That led to referee Anthony Taylor going over to the touchline before ordering the stadium announcements, implementing a procedure initially formed by FIFA to deal with discrimination in games.

“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,” Rüdiger said. "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 that the offenders will be found and punished soon, and in such a modern football ground like the Tottenham Hotspur Stadium with dozens of TV and security cameras, it must be possible to find and subsequently punish them.”

Tottenham said it had launched an investigation and would be liaising with Chelsea and its players.

“Any form of racism is completely unacceptable and will not be tolerated in our stadium,” Tottenham said. "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.”

Chelsea manager Frank Lampard said he would support his players walking off the field in future.

“It would depend what the players were feeling and saying,” Lampard said. “I'm sure it would be a group decision. But we're not there yet, so it's hypothetical to a degree.”

Repeated announcements warning against racism in stadiums would typically indicate multiple incidents and require the players to be taken off. But Tottenham and the Premier League said there had been only one reported incident.

“I'm disappointed that things like that still can happen,” Tottenham manager Jose Mourinho said after his team's 2-0 loss. "But the referee stopped the game, he 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.”

If the English Football Association followed sanctions used by UEFA and FIFA, part of Tottenham's stadium could be ordered to be closed to fans as a punishment.

“We will not allow this to continue,” the Professional Footballers' Association said in a statement. “Now more than ever we must unite and stand strong and together to confront, challenge and eradicate racist abuse in our stadiums and in our country.”

The Manchester derby two weeks ago was also marred by a high-profile incident of racism when United players were targeted with abuse at City.

The England national team experienced a European Championship qualifier being stopped twice in Bulgaria in October when home fans made Nazi salutes and targeted monkey noises at the visiting black players

“Racist abuse in football is not just an issue for black and ethnic minority players, it is an issue for everyone who loves the game,” the players' union said. “We believe that the time has come for all governing bodies to unite collectively to end this abuse. ...

“All football stakeholders must work in partnership with police and clubs to drive this issue and accelerate solutions.”