[PHOTO: COURTESY]

CSKA Moscow fans chanted racist abuse at Arsenal's black players several times during a Europa League match late on Thursday, a Reuters witness has claimed.

According to the news agency one of their photographer at pitch level heard dozens of home supporters make monkey chants towards Arsenal's Danny Welbeck and Alex Iwobi as they neared a section of the stands when the ball went out of play.

Arsene Wenger’s men looked in serious danger of going out in Moscow until Welbeck hit a 75th minute goal, with Aaron Ramsey confirming their passage to the semis with a 90th minute strike.

That made the match 2-2 on the night, and 6-3 on aggregate.

Iwobi came on as a second half substitute when he replaced Alexander Lacazette in the 77th minute.

The chants were heard when Welbeck celebrated his goal that brought Arsenal back into the game from 2-0 down, the photographer said.

A third Arsenal player who did not come off the substitute's bench was targeted with the same chants after the final whistle as he jogged to warm down on the pitch at the CSKA Arena, the witness said.

The player, who Reuters was unable to identify, was also black.

Russia faces increased scrutiny over fan behaviour ahead of the World Cup it hosts starting in June and the country has pledged to crack down on racism. [PHOTO: COURTESY]

UEFA told Reuters on Friday that no racist behaviour had been reported to it by match officials at the game.

UEFA said it had opened disciplinary proceedings against CSKA Moscow on Friday for infractions including throwing objects and setting off fireworks. The alleged infractions were not connected to racist or discriminatory behaviour.

The European soccer body said it took allegations of racist behaviour very seriously and it would be grateful for audio or video evidence of any other incident as it required sufficient proof to be able to press charges.

The Russian Football Union declined to comment.

Reuters made repeated calls to a mobile number for a CSKA spokesman but there was no reply. An email to the club was not answered.

A spokesman for Arsenal declined to provide a comment for publication.

After the match Gunners boss Wenger said: “CSKA made my heart beat much quicker than I expected it to be. If you look at the game we were in trouble.

“We were not at the races in first half. They scored the second and even then they have another chance to make it three. Then we were a bit on the ropes but we had a good response.

"I repeat the same after every game about Danny Welbeck. I would say above all the qualities, when you have back to the wall, he looks like he has an extra special motivation in his body and head to give you something special.

"That is something really exceptional, you do not find it in many players."

CSKA Moscow have also been charged with the setting off of fireworks and the throwing of objects in contravention of UEFA's disciplinary regulations at the match.

The Russians have also been charged with blocking stairways in contravention of UEFA's safety and security regulations.

This case will be dealt with by UEFA's control, ethics and disciplinary body on May 31.