"In general it's always a good sign to have the opportunity to extend contracts early," said Klopp.

"If we can keep these boys together, we are in the middle of our development, so it's good news for Liverpool.

"These 17-18 players plus the really young boys, that's the squad of the future. It should be like this.

"It's investment, the club gave us the opportunity to do it. Really nice.

"Progress is something everybody should expect. The club gave us fantastic opportunity to bring in outstanding players, to keep outstanding players. My job is to make sure we perform on the pitch.

"Where will we be in two or three years? I have no idea but the age group is good. This season will not finish our development.

"It doesn't look like we'll lose any key player (and) we build a new training ground, another step in the future."

In looking after the long-term Liverpool are likely to offer youngster Ki-Jana Hoever a professional contract after he turned 17 on Friday, although Klopp said it was not their immediate priority.

The Dutch youth international, who has been training at Melwood over the last month, became the third-youngest player in the club's history when he made his debut in the FA Cup defeat at Wolves.

"He can sign professional now. If you turn 17, life should be really cool, yeah?" added Klopp ahead of the Premier League leaders hosting Crystal Palace on Saturday.

"There are big steps to make for all of these boys. Ki-Jana will be fine, he is really happy in the moment, we showed him where he will be in the future, now he has to make all the steps alone, but supported by us.

"Contracts are no concern in this moment; there were plenty of reasons for him to join us. The boys are here, and now we work with them."

There was a less optimistic outlook for fellow young prospect Rhian Brewster.

The 18-year-old was expected to be involved in Klopp's squad this season when he had recovered from knee and ankle ligament damage but setbacks mean he will not be ready until pre-season.

"He's not as far as he would like to be. He's outside training, his running looks much better since he had this other little surgery," said Klopp.

"It's no problem, he has the time. We don't have to think about him before the pre-season, I would say.

"He's a nice fella, really integrated in the team, but so far he couldn't show it on the pitch.

"But our opinion about him will not change. We have to wait a little longer for him."

The situation is different for Alex Oxlade-Chamberlain, however. The England international is ahead of schedule for his comeback – which was not expected to be until next season – from significant knee ligament damage sustained in April.

"When I see him running, moving with the ball and all the stuff – which he is all doing already – it looks really good, promising, close to a return," said the manager.

"It will be fine; it looks completely without any problems in the moment, no swellings any more.

"He can really work already on his fitness issues, which he's had for a long time. I think we will see him this season."

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