Koren is competing at the Giro d'Italia and will not be allowed to start Wednesday's stage according to the regulations.
Italian Pettachi, 45, retired in 2015, while 38-year-old Slovenian Bozic ended his cycling career last year and is now Assistant Sports Director at Team Bahrain Merida.
The four are under investigation for employing prohibited doping methods between 2012 and 2017.
"The UCI and the Cycling Anti-Doping Foundation (CADF)... have been in close contact with the sport and state authorities involved in the Aderlass investigation, in particular with the World Anti-Doping Agency (WADA) and the Austrian law enforcement authorities," UCI said in a statement.
Operation Aderlass is looking into blood doping, a process where athletes have blood transfusions to increase their stamina and performance -- a method prohibited under WADA regulations.
The provisional suspension begins on the day of the notice and a UCI Anti-Doping Tribunal will be established to hear the anti-doping rules violations.
UAE Team Emirates have suspended 31-year-old Durasek.
"The Team hopes that Durasek can prove he was not involved in the affair. Should it be proven otherwise, he will be terminated immediately," they said in a statement.
Team Bahrain Merida have also provisionally suspended 32-year-old Koren and Bozic.
"The team strictly advocates zero-tolerance doping policy and has therefore provisionally suspended both members concerned," the Bahrain-based team said in a statement.
"We would like to stress that both cases relate to the 2012 and/or 2013 seasons. The team always carries out thorough medical checks (including biological passport checks) of any new signed rider."
(This story corrects ICU to UCI in headline, no change to story)
(Reporting by Rohith Nair in Bengaluru; Editing by Amlan Chakraborty and Ken Ferris)
