Arsenal's Brazilian forward Gabriel Jesus is set for a lengthy spell on the sidelines after suffering what is suspected to be an anterior cruciate ligament (ACL) injury, according to British media reports on Tuesday.

Jesus, 27, left the pitch on a stretcher before the end of the first half in Arsenal's FA Cup tie with Manchester United on Sunday, which Mikel Arteta's side lost on penalties.

"We know more now. It is not looking good at all. We need to review with one more specialist and will have better information this afternoon," Arteta told a press conference ahead of Arsenal's Premier League game with Tottenham Hotspur on Wednesday.

"I don't want to confirm anything until we have the final report this afternoon. We were very worried after the game and we are very worried today."

Jesus had just recently hit goalscoring form, netting his first league goals of the season when scoring a double against Crystal Palace in December, and scored another in a win over Brentford on New Year's Day.

He also scored a hat-trick against Palace in a League Cup quarter-final game last month. Jesus joined Arsenal in 2022, having won four league titles with Manchester City.

Arsenal may now look to bring in a new striker during the January transfer window, but according to the manager, it is not the only area in which they may need to invest.

"We have other issues as well. A player can bring things to a team in different ways. That is what we are trying to do," Arteta said.

"We are actively looking in the market to improve the squad. We would be naive not to do that. There is an opportunity to improve the squad."

Arteta also spoke about the online abuse suffered by Kai Havertz, after the forward had his penalty saved during Sunday's shootout, which led to Arsenal exiting the FA Cup in the third round.

"It is incredible, honestly. We really have to do something about it," Arteta said.

"Accepting and hiding this has terrible consequences. It is something we have to eradicate from the game.

"On the 27th December we won 1-0 and Kai Havertz scored the goal. That was 20 days ago. Guys, what is the perspective? We are all responsible for the narrative and how we talk."

Arsenal, second in the league standings and six points behind Liverpool who have a game in hand, host Spurs who are 12th, in the north London derby.

"It is the nicest game of the season to watch and play because of the atmosphere and what it means to the people, us and everyone that is involved," Arteta said.

"The atmosphere is something the fans can help with and something we can do by giving them something to feed off."