The comment came as Kuleba was speaking with Ukraine 24 TV, Ukrinform reports.
"A little more than 20 years ago, Western powers told Lithuanians, Latvians, and Estonians in the same mentoring tone: you need 20-30 years to mature to get to the EU and NATO. So, of course, I was surprised to hear these words from the president of Estonia. I had talked to her prior to that and she was optimistic. I don't know what influenced her during the interview, but these statements do not correspond to the friendly nature of our relations," the minister said.
According to him, MFA Ukraine has already conveyed to the Estonian Foreign Ministry its indignation over the said statement.
"We are disappointed with such statements and consider them inappropriate. We have brought this position to the Estonian Foreign Ministry, to the Estonian ambassador to Ukraine. We believe such things should not be voiced by friends and partners," the top diplomat said.
Earlier, Estonian President Kersti Kaljulaid said the EU should be bolder in its enlargement as regards Eastern partners, but Ukraine, Moldova and Georgia need another 20 years of work to get prepared for EU membership.