Erdogan lambasts Brussels over EU-Arab summit
Egypt on February 20 hanged the nine men for the 2015 assassination of prosecutor general Hisham Barakat, despite pleas from human rights group Amnesty International.
Around 40 EU and Arab leaders met after during a two-day summit which began on Sunday in the Egyptian Red Sea resort of Sharm el-Sheikh hosted by President Abdel Fattah al-Sisi.
"Can we talk about democracy in EU member countries who accepted the invitation of Sisi, who has executed 42 people since he came to power and nine young people last week, although capital punishment is banned (in the EU)?" Erdogan said during a speech in the northeastern province of Giresun.
"Can we talk about rights and freedoms over there?... It is not possible to understand them. The EU is not sincere."
Turkey-Egypt relations are almost non-existent since the Egyptian military, then led by Sisi, ousted Islamist president Mohamed Morsi, an ally of Erdogan, in 2013.
Although Morsi's Muslim Brotherhood is outlawed in Egypt, members of the group have sought refuge in Turkey.
Turkish Foreign Minister Mevlut Cavusoglu said earlier that it was "an example of double standards, hypocrisy that the EU leadership would give support to Sisi and be in the same place as him in the days after nine people were martyred, were executed."
"When we look at the leaders who run Europe today, including the EU, there are no values, there are only interests," he told reporters in Ankara.
Cavusoglu also hit out at the EU's "hypocrisy" over its criticism of Turkey when there were concerns that the death penalty could return after the July 2016 failed coup.
Turkey abolished capital punishment in 2002 but since 2016, Erdogan has at times suggested the death penalty could be reinstated if a bill was approved by MPs.
Relations between Ankara and Brussels have been strained, especially since 2016 over the EU's criticism of the scale of the post-coup crackdown and Turkey's claim the bloc failed to show solidarity after the attempted overthrow.
Amid EU tensions, Turkish foreign ministry spokesman Hami Aksoy last week said it was "absolutely unacceptable" that the European Parliament foreign affairs committee called for Ankara's membership negotiations to be officially suspended.
Follow us on Twitter: @The_NewArab