Liverpool will be without key duo Mohamed Salah and Roberto Firmino for the second leg of their Champions League semi-final against Barcelona, Jurgen Klopp has confirmed.

Salah, Liverpool's leading scorer in all competitions this season, sustained a head injury in the Reds' 3-2 victory over Newcastle United on Saturday. 

The Egypt forward had to be taken off on a stretcher in the 73rd minute, with his replacement Divock Origi scoring the winner 13 minutes later. 

Speaking ahead of Barca's trip to Anfield, Klopp confirmed Salah had suffered a concussion but will be fit for Sunday's decisive final-day Premier League clash against Wolves. 

Firmino, meanwhile, missed the Newcastle clash with an ongoing groin problem, and will remain on the sidelines as Liverpool look to overturn a 3-0 deficit.

"Both are not available for tomorrow," Klopp told a news conference. 

"[With Salah] it's concussion so he wouldn't be allowed to play. That's it. 

"He feels okay, but it is not good enough from a medical point of view. That's all. He's desperate [to play in] everything, but we cannot do it." 

When asked if Salah will be available for the weekend, Klopp replied: "Yes." 

Luis Suarez and Lionel Messi put Barca in control of the tie at Camp Nou on Wednesday, with Salah hitting the post late on. 

Liverpool responded with a hard-fought 3-2 win at St. James' Park, moving back to the top of the Premier League, with Manchester City hosting Leicester City on Monday. 

It was a result that means the title will be decided on the final day of the season, when City travel to Brighton and Hove Albion as Liverpool take on Wolves at Anfield.