(Reuters) - The Turkish Athletics Federation (TAF) has given two-year suspensions to 31 athletes for drug violations, it announced on Monday.
At least three of the athletes competed at the 2012 London Olympics, including hammer thrower Esref Apak, the 2004 silver medalist.
Bans had been expected after the International Association of Athletics Federations (IAAF) conducted a large number of tests ahead of and during the Mediterranean Games in the Turkish city of Mersin in June.
Apak was one of eight athletes who tested positive following the European Team Championships in Gateshead the same month.
Last week, TAF chairman Mehmet Terzi resigned from the post he had held for nine years in the face of doping allegations directed at Turkish sportsmen and women.
"The athletes were found to be in violation of Turkey's strict anti-doping laws following testing undertaken by the Turkish anti-doping authority (TADA)," Ugur Erderner, president of Turkey's National Olympic Committee and a member of the World Anti-Doping Agency (WADA) executive board, said in a statement.
"TADA conducted the tests either as part of their own anti-doping programs, or in conjunction with the IAAF and WADA.
"This work is part of a concerted, and much more aggressive, anti-doping policy in Turkey that has been in place for over six months and will be further reinforced with the re-accreditation of the WADA-licensed anti-doping laboratory in Ankara later this year."
Erderner said an anti-doping education program would be introduced in schools and colleges.
"Turkey has zero tolerance for doping and it is our intention to have clean, young athletes competing on the international sporting stage in the future."
The TAF listed the names of the suspended athletes on its website (www.taf.org.tr), without giving details of their offences.
Istanbul is bidding to host the 2020 Olympics.
(Reporting by Josh Reich in London; Editing by Clare Fallon)