During today's ceremony, President Zoran Milanovic abruptly left the event in protest against the salute "For the homeland ready" on T-shirts of some of war veterans who arrived in Okucani to participate in the commemoration.
The salute concerned, which was used during the Ustasha regime in the Second World War, was also used by the HOS volunteers during the 1991-1995 Homeland War.
Milanovic later explained that he was sorry but he found the T-shirts to be an act of provocation and trampling on the sacrifice of all who gave their lives for Croatia.
The wreath-laying ceremonies were held by Parliament Speaker Gordan Jandrokovic, Prime Minister Andrej Plenkovic, and government minsters as well as by the police and army delegations.
Defence Minister Krsticevic said in his statement to the reporters that a key to the success of Operation Storm was the bravery of the Croatian soldiers.
The operation was launched on May 1 and ended on May 3, 1995. During less than 32 hours Croatian troops and police regained control of 500 square kilometres of land, including the main west-east motorway and the railway line leading to Eastern Slavonia.
About 7,200 troops and police officers took part in the liberation of Western Slavonia, of whom 42 were killed and 162 wounded.
It was the first time during the 1991-1995 Homeland War that the Croatian Air Force had used airstrikes on a larger scale, and the enemy was further surprised by tanks that were brought in by rail and deployed in combat.
Okucani is located about 130 kilometres southeast of Zagreb. During the war it was the centre of the Serb rebellion and a staging area for terrorist attacks in Western Slavonia.
After their defeat in western Slavonia, the Serb insurgent leaders organised and ordered the missiles attacks on Zagreb, Karlovac and Jastrebarsko. During the attacks against Zagreb on 2 May 1995, seven civilians were killed and 218 wounded, while the attacks on Karlovac and Jastrebarsko only caused property damage.
Serb rebel leader Milan Martic was sentenced by the UN tribunal ICTY to 35 years for war crimes committed during those missile attacks.