Former Cameroon and Barcelona striker Samuel Eto'o has apologised for what he described as a "violent altercation" at the World Cup in Qatar on Monday night.
A video circulating on social media appears to show the 41-year-old kneeing a man in the head outside Stadium 974 in Doha.
In a statement, Eto'o, who is president of his country's football federation (Fecafoot), said he was provoked by a fan who was "probably" an Algeria supporter as part of an ongoing campaign of harassment following Cameroon's qualifying win over Algeria in March.
"After the Brazil-South Korea match, I had a violent altercation with a person who was probably an Algerian supporter," Eto'o wrote on his social media channels.
"I would like to apologise for losing my temper and reacting in a way that does not match my personality. I apologise to the public for this unfortunate incident."
The video initially appears to show Eto'o happy to pose for pictures with fans in the area outside the stadium, which staged the last-16 match between Brazil and South Korea on Monday.
However, he then seems to react to something and is initially restrained from attacking a man by those around him.
He breaks away from those individuals and appears to strike the man in the head with his knee.
Eto'o, 41, has been a global ambassador for Qatar's World Cup organising committee since 2019.
That committee has been contacted for comment, along with tournament organiser FIFA, Fecafoot and the Qatari government. Algeria filed a complaint over the performance of the referee in the qualifying play-off in Blida, in which Cameroon's Karl Toko Ekambi scored the winner with the last kick of the match.
Eto'o added: "I pledge to continue to resist the relentless provocation and daily harassment of some Algerian supporters.
"Indeed, since the Cameroon-Algeria match on 28 March in Blida, I have been the target of insults and allegations of cheating without any evidence."

A video of Louis van Gaal dancing into the team hotel after his team's victory over the United States went viral and there is no shortage of joy in the Netherlands camp as they prepare to face Argentina in the World Cup quarter-finals.
No strangers to a bit of in-fighting in the past, this Dutch squad is very much united as they gear up to face Lionel Messi and company on Friday with a semi-final place up for grabs.
"The vibes are good, we have a lot of fun times with the team, the communication with the trainers and the staff is very good. So yeah, the feeling is great," defender Jurrien Timber told reporters on Tuesday.
Defender Nathan Ake said the players felt very much together.
"We know when to relax and get our heads a little bit out of the football, but we know when to focus as well, and that time is coming very soon," he added.
Barring the path to the last four is an Argentina team powered by Messi, who is trying to win the one major prize to elude him in his glittering career.
Ake, who works with Messi's former coach Pep Guardiola at Manchester City, has not asked his boss how to stop the Argentine maestro.
"No, I haven't spoken to him, but if I did I'm sure he would tell me it will be pretty tough. It will be a good battle for sure," Ake said.
Much will depend on what Van Gaal decides to do tactically.
"Ever since he's came in, he's been great for us. I think he's very direct. He lets everyone know where they stand ... you know exactly what your role is in the team, and off the pitch he's a good guy as well," Ake said.
The players have been inspired by Van Gaal's stoic battle with cancer, which he did not reveal to the squad during qualifying, and with the 71-year-old due to step down after the World Cup they want to send him out in style.
"He doesn't want any sympathy or anything like that. He just wants for us to do well and you can see his enjoyment in the games if we do well, I think that is his enjoyment," Ake said.

Germany team director Oliver Bierhoff has become the first casualty of their first-round World Cup exit in Qatar after agreeing to leave his post two years before his contract ends.
Former Germany international Bierhoff, who had been in his post as team director for the last 18 years, was widely criticised following their second consecutive shock early exit at a World Cup.
"Oliver Bierhoff has won a lot of merits for the DFB," said DFB president Bernd Neuendorf in a statement.
"Even if the last few tournaments lagged behind the sporting goals that had been set, he will be associated with big moments."
Bierhoff played a part in helping Germany win the last of their four World Cup titles in 2014 and Neuendorf said his efforts would not be forgotten.
"He will always be linked with the World Cup success in Brazil," he added. "Even in turbulent times he always followed goals and visions."
Germany crashed out of the tournament in Qatar after losing to Japan, drawing with Spain and beating Costa Rica in the last Group E match. Spain and Japan advanced from that group.
The Germans had also tumbled out of the 2018 World Cup at the same stage - at the time their earliest exit in 80 years.
They also failed to advance past the round of 16 at Euro 2020 last year.
Germany football bosses will hold their first meeting on Wednesday to analyse their recent tournament performances and to plan improvements ahead of Euro 2024, which the country will host.

Olivier Giroud believes his France scoring record is a great example for young players because it was a reward for his resilience after a career featuring many ups and downs.
Giroud surpassed Thierry Henry's mark when he netted his 52nd goal in 117 appearances for Les Bleus in their 3-1 World Cup last-16 win over Poland to become France's all-time top scorer.
It did not come easy for the 36-year-old, who has rarely been considered a first choice for his country.
He owes his place in the team in Qatar to Karim Benzema's absence and will start again when the defending champions take on England in the quarter-finals on Saturday.
Giroud made his debut in Ligue 1 with Montpellier at the age of 24 before winning his first cap for France a year later.
After last year's European Championship exit in the last 16 against Switzerland, Giroud was omitted by coach Didier Deschamps until March.
"This record reminds me of the years that have gone by, 11 years with France with a lot of good memories and some not so good," Giroud, who answered questions in French, English and Italian, told a news conference on Tuesday.
"I think the most important is to show a good example to the young players, to show them that even if the path they're on is not a straightforward path, they can do it.
"I wasn't playing at the highest level at 20, so if it can serve as an example that anything is possible, it's great. It shows that you can't get everything right away, like the youngsters want now, that resilience and patience are key."
Giroud's career appeared to be stalling but he joined AC Milan in 2021 and was rejuvenated.
"I had to find another challenge for myself. It was a great opportunity for me to play for the great Milan, I wanted to do everything right because I knew I still had a few good years ahead of me," said Giroud, who has scored 23 goals in 57 appearances for the Rossoneri.
"I was confident I could do well and in my first year we won the Scudetto (Italian league title)."