The North London side are the only top-flight team not to have strengthened so far this summer and have instead sold Kyle Walker to rivals Manchester City for £50m.
Earlier this week, Spurs defender Danny Rose publicly criticised the club for their lack of transfer activity, saying that they need "one or two big-name signings" if they are to improve upon their second-place finish in the Premier League last season.
"If you see the last five years, Tottenham always spend money and sign players at the end of the transfer window. I don't understand why it's a big issue now," Pochettino told reporters today.
"We will add players who can strengthen the squad. We will work hard until the end to add more possibilities to have in the future. With the players we have we can compete in a very good way.
"Of course, we will sign, like every season, maybe on the last day. We will sign players we believe can help us to challenge for the things we want to challenge for."