President Ivo Josipovic and Prime Minister Zoran Milanovic are delivering eulogies.
Several foreign delegations have announced they will attend the funeral - Slovenian Parliament Speaker Gregor Virant, Bosnian lower house Deputy Speaker Denis Becirevic, the president of Bosnia and Herzegovina's Federation entity, Zivko Budimir, Serbian Parliament Speaker Zarko Korac, Kosovo Parliament Deputy Speaker Dzavid Haliti, Czech Senate Vice President Alena Paleckova, Macedonian Parliament Deputy Speaker Svetlana Jakimovska, and the vice president of the Croatian-Austrian Friendship Group and Austrian parliament speaker envoy Oswald Klikovits.
Mass will be said by Auxiliary Zagreb Bishop Mijo Gorski.
After the service, the procession, accompanied by Croatian Army servicemen, will head for the vault where Sprem will be buried with the highest military honours.
A memorial service will be held in St. Mark's Church at 6 p.m.
Sprem's casket is lying in state since early this morning.