On a four-day fact-finding trip to Turkey, EU Enlargement Commissioner Guenter Verheugen said on Tuesday Kurdish language education and broadcasting were areas that needed more attention.
He said Turkey must also increase efforts to let displaced Kurds return to villages destroyed in a 20-year separatist conflict.
Verheugen's conclusions come a month before the EU publishes a progress report on 6 October.
The report will influence a decision by EU leaders in December on whether to open full accession negotiations.
Verheugen pledged that the commission would provide an objective analysis of Turkey's drive to meet European standards and deliver a clear recommendation.
"The critical message will be a clear and firm decision," he said.
"We agree that now the moment of truth is coming. I made it very clear: nothing can and must postpone the decision that is foreseen for December," Verheugen told reporters after meeting Turkish Foreign Minister Abdullah Gul on Monday.
The EU official applauded the reforms that Turkey has made over the past four years.
Verheugen praised Ankara's efforts to clean up its human-rights record, a key demand of the European Union.
Visiting Kurdish villages was part
of Verheugen's fact-finding trip
"We will not hide the fact that there are difficulties in some areas and that, of course, implementation is not complete. But that's normal," he said.
Asked about allegations of torture in Turkey, Verheugen said it was "very difficult" to say whether the practice existed systematically in Turkey.
"Obviously there is important progress," he added.
Turkey, which has been an EU candidate since 1999, argues that a raft of reforms it has adopted has enabled it to fulfil most of the political criteria needed to get the go-ahead for the start of accession talks.
In a separate development on Monday, Dutch EU Commissioner Frits Bolkestein has said, "Whoever allows Turkey in will also have to accept Ukraine and Belarus. Those countries are more European than Turkey."
In a speech to a Dutch university on Monday, Bolkestein cautioned that "Europe would become more Islamic".
"Whoever allows Turkey in will also have to accept Ukraine and Belarus. Those countries are more European
Dutch EU Commissioner
Saying that "immigration pressure" from the south would mount dramatically, he quoted Bernard Lewis, a US historian, as saying that by the end of this century Europe would be predominantly Islamic.
"If he [Lewis] turns out to be right, the relief of Vienna in 1683 will have been in vain," Bolkestein said, referring to the defence of fortified Vienna by Polish, German and Austrian forces in the face of a siege led by Ottoman Turks.
It is the second time this year Bolkestein has openly questioned the accession of Turkey, a politically secular Muslim country.
Bolkestein's spokesman, Jonathan Todd, declined to comment on the commissioner's speech.