Jurgen Klopp says Liverpool are still planning to add during the summer transfer window, with their squad lacking depth at present.
The Reds have been relatively quiet on the recruitment front so far, with deals done for Mohamed Salah, Dominic Solanke and Andy Robertson.
With Champions League competition set to be added to their workload again this season, Klopp acknowledges that more bodies are required.
He told reporters: “We are still working on all parts.
“We are in talks and we work on all parts of the game. The squad at the moment is not too wide for a lot of games. That’s it.”
Calls for Liverpool to step up their long-standing interest in Southampton centre-half Virgil van Dijk are growing in intensity, with their defensive frailties – particularly from set-pieces – exposed once again in a 3-3 draw with Watford on Saturday.
Klopp added: “We have to defend better.
“Of course we know it’s an important thing. I don’t feel comfortable but I know what to do.
“We got things wrong and what do I want to do to sort it? Buy a new player in that position? I am not really sure if it makes sense. We have to work on it because we did well in pre-season in this situation.”
Klopp has previously declared that he has no need for another centre-back, with the likes of Joel Matip, Dejan Lovren, Mamadou Sakho and Ragnar Klavan already on his books.
Former Reds favourite Jamie Carragher is not convinced that Van Dijk would be the answer either, with it his opinion that tactics, rather than personnel, are to blame for Liverpool’s struggles.
He told Sky Sports: “It’s down to the manager and one man won’t change Liverpool’s defence – on average they concede almost 50 goals a season.
“Their set-pieces are the worst in the league. You see the same thing year in, year out. It’s not rocket science, set-pieces and counter-attacks.”
Liverpool are next in action on Tuesday when they head to Germany to take on Hoffenheim in the first leg of their Champions League play-off tie.