The 23-year-old forward, who joined Liverpool from Burnley in the summer and has scored three goals in his eight appearances -- including the strike at Everton in their last match under Brendan Rodgers two weeks ago -- is likely to miss the Euro 2016 finals next summer.
Ings, who came on as a second-half substitute in the Euro 2016 qualifier against Lithuania on Monday, was injured during new coach Juergen Klopp's first session in charge on Wednesday and is the second Liverpool player to suffer a serious long-term injury this week.
Young defender Joe Gomez, who signed from Charlton Athletic in the summer and has played seven times for the club, was injured playing for England Under-21s against Kazakhstan on Tuesday.
The injury to Danny Ings leaves Belgian youngster Divock Origi, who has made four appearances for the club, as Liverpool's only fully fit striker.
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Christian Benteke is still recovering from a hamstring injury and Daniel Sturridge has played just three times after a series of injuries curtailed his appearances last season.
Roberto Firmino, another attacking option for Klopp, has not played for three weeks, and will not be fit in time for Liverpool's match at Tottenham Hotspur on Saturday.
(Reporting by Mike Collett,; Editing by Neville Dalton)
