Tottenham says the findings of its initial investigation into alleged racial abuse aimed at Antonio Rudiger is "inconclusive" as the club calls in lip-readers to assess CCTV footage.

Rudiger told Chelsea club captain Cesar Azpilicueta that he was subjected to racist chants during its 2-0 win at Tottenham Hotspur Stadium on Sunday.

The Germany international was allegedly targeted shortly after Spurs' Son Heung-min had been sent off for kicking out at his opponent.

Referee Anthony Taylor called for an announcement to be made over the stadium's public address system to warn fans against making abusive chants.

In a statement issued on Monday, Spurs said: "We are able to track every fan via the cameras and have spent many hours reviewing CCTV footage. We have engaged lip-readers to study the footage and contacted Chelsea for further information from their players.

"We have also taken statements from other parties present at the time. The police will be reviewing our evidence alongside us. Please be assured we shall be exhaustively investigating this matter.

"This club has a proud track record of anti-racism work across all our communities and we are determined to ensure that we conduct a thorough investigation. Any fan found to be guilty will receive a lifetime ban.

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"At this time however we should point out that our findings are inconclusive and would ask that comment is reserved until the facts are established."

The stadium announcement was repeated three times during the match, leading to speculation that racist abuse continued after the first warning.

Spurs say the confusion came about as Taylor implemented UEFA anti-discrimination protocols, rather than those outlined by the Premier League.

"When the incident was conveyed to the referee Anthony Taylor, he took the decision to call for the implementation of Stage 1 of the UEFA protocol – rather than the Premier League protocol – and asked for an announcement to be made, as well as requesting a further announcement which created a misconception that any issue was on-going," the club said.

"The Premier League protocol differs from UEFA protocol in that it does not call for an announcement rather that the individual(s) be dealt with by the Safety Team in the first instance.

"We have asked that the Premier League clarifies the position regarding the use of these protocols to all stakeholders going forward."