Late Molina stunner dumps Liverpool out of FA Cup
With a deadline for mid-season deals coming up on Wednesday (AEDT), Klopp declared there would be no new faces arriving at Anfield.
Klopp told beIN SPORTS: "No, nothing will happen in this transfer window, that's all."
Liverpool's last trophy hope for this campaign lies in the Champions League, where they face Real Madrid at the last-16 stage, having lost to the Spanish giants in last year's final.
The Reds are out of both domestic cups and sit only ninth in the Premier League, having won just eight of their opening 19 games in the competition. Across all competitions, they have already lost nine times in 31 outings this term.
Klopp picked fault in the body language of several of his players in the 2-1 fourth-round loss to the Seagulls, which followed 15 days on from a 3-0 league defeat to the same opposition at the Amex Stadium.
He also wrote off Liverpool's set-piece defending as a major disappointment, with Brighton twice punishing the Reds from such situations.
"That doesn’t feel great, obviously. That's not cool, but we have to take it," Klopp said.
He said: "We have still space for improvement. We make steps, but we have to improve, we have to improve further on and that's what we will do."
Klopp felt the performance of his players on Sunday was far better than in their league display against Brighton, but these are small comforts.
Liverpool is in a crisis that is only deepening as their German boss fails to deliver results, despite being backed in the transfer market, with Dutch World Cup star Cody Gakpo arriving this month from PSV.
It faces Wolves in the league next weekend, before a derby against Everton and a trip to high-flying Newcastle United precede the Champions League first leg against Madrid.
"If we are in a better situation, 10 points more in the league and stuff like this and then you lose here at Brighton, you just say, 'Respect'. What they do is really good," Klopp said.
"But we are obviously in a situation where we constantly want to make the final step, and that's why it feels now especially bad in this moment because it didn't happen.
"But there were, again, steps in the right direction. You can imagine nobody wants to hear that any more, I cannot hear it any more, but it's still right. That means we have to go from there.
"We have to improve, we have to do better, the body language with a couple of boys has to be much better, defending in the formation has to be better from a few."
Klopp felt Liverpool lacked a little luck, with Lewis Dunk deflecting in Brighton's leveller from Tariq Lamptey's shot before the winner came from Kaoru Mitoma in second-half stoppage time.
"You should not forget that," said Klopp, "but we are still out and that's obviously the worst outcome of a game you can have."