Arsenal manager Mikel Arteta said this summer's transfer window has been the "most difficult" for years but is hopeful of adding to his squad before the deadline passes.
Arsenal have so far signed Ben White, Albert Sambi Lokonga and Nuno Tavares for combined fees totalling around £75 million. However, they remain in the market for a creative midfielder with Leicester's James Maddison and Lyon's Houssem Aouar among their targets, a back-up goalkeeper and possibly a striker depending on departures elsewhere within the squad.
Hector Bellerin has an agreement to leave this summer while Joe Willock is closing in on a move to Newcastle and there are uncertainties over several other players with Arsenal needing to raise money through sales to help fund Arteta's rebuild.
"It has been really busy and you've just named a few names but that tells you as well how much we've had to do from the position that we started the window," the Spaniard said on Thursday, ahead of their opening Premier League game at Brentford.
"We are talking about probably the most difficult transfer market in this industry over the last years for sure and we are trying to adapt. The club, the owners and myself, we all have the same interests, which is to make this team much stronger and we know that we still have things to do to get what we want.
"[Money is tight] for every club at the moment, we have an ownership that is willing to invest in the team and they want to get the team better and with bigger aims and we are trying to find the balance because at the same time we need to be really careful because we need 100% a position that is sustainable and will help the club."
Arteta hinted their decision making will be influenced by the requirement to name at least eight "homegrown" players in their final 25-man Premier League squad.
A homegrown player is defined as someone who spent at least three years with a club in either England or Wales between the ages of 15 and 21.
"I think everything is related to who we bring in, who is out, our capacity to hold foreign players in the squad," he added. "There are a lot of question marks still to be resolved. It's still pretty open."