Jurgen Klopp films Liverpool stars on the treadmill in pre-season training

Liverpool's stars were shown hard at work on the treadmills as they stepped up their preparations for the new season on their tour of the USA.

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But in a twist it was Jurgen Klopp who filmed his self-acclaimed 'most expensive running group in the world' on the club's Instagram account.

Klopp joked around with Virgil van Dijk, Georginio Wijnaldum, Mohamed Salah, Marko Grujic and Sadio Mane as he egged them on in their training regime.

The German joked he would send Dutch pair van Dijk and Wijnaldum 'back to Holland'.

As the camera then panned to last season's Player of the Year Salah, he asked: 'Why don't you run?'

The grinning Egyptian panted back, 'I'm running boss' as he put in the hard yards.

Serbian midfielder Grujic, on the treadmill next to Salah, joked: 'He's tripping already', to which Klopp agreed.

Finally the Liverpool boss filmed Mane on the far treadmill, who attempted to keep a straight face in front of the camera.

But as Klopp said, 'Come on Sadio, give us a smile. That's not a smile', the Senegalese forward eventually caved.

Klopp laughed and told the 26-year-old, 'You cannot avoid smiling right!'

The Reds return to action on Wednesday night when they face Premier League rivals Manchester City at the MetLife Stadium in New York.

In their opening International Champions Cup game on Sunday Klopp's side fell to a 3-1 defeat by Borussia Dortmund.

Van Dijk had headed them into a first-half lead before a Christian Pulisic brace and a stoppage time strike from Jacob Larsen secured victory for the German outfit.