State and other delegations laid wreaths and lit candles at the town's Memorial Cemetery of Homeland War Victims to commemorate the Vukovar tragedy.
Wreaths were laid and candles lit by President Stjepan Mesic, Parliament Speaker Vladimir Seks, and Prime Minister Ivo Sanader.
Mesic said that today Croatia remembered the pain and sufferings of Vukovar residents who wanted nothing else but to leave in peace in their home town.
Tribute was also paid by delegations of Homeland War associations from Vukovar, Vukovar County authorities, the cities of Vukovar and Dubrovnik, the OSCE Mission to Croatia and retired Croatian Army Generals.
Proceeding in a column through the streets of Vukovar towards the town cemetery, Mesic recalled the wounded people who were taken from the Vukovar hospital to be executed, stressing this was disturbing for everyone.
"The enemy wanted to break down Vukovar, because they though this would break down Croatia, which is why it is good that we came here to remember those who did not allow that Croatia be broken down," Mesic said
He stressed it was most important to reconstruct the city and enable people to return and have a better life than those who gave their lives for Vukovar.
Seks said that today he remembered all those who died while trying to protect this eastern city and resist the Yugoslav People's Army three-month siege.
We are remembering the days of pride and glory but also the fact that life must go on and that, because of the victims, we must rebuild Vukovar and entire Croatia, Seks said.
He also said that the reconstruction of Vukovar was proceeding well, stressing, however, that more efforts needed to be invested in creating new jobs and climate favourable for entrepreneurship.
Sanader said he remembered with sadness the tragedy that happened to this eastern town 15 year ago, but that he was also proud because Vukovar was also defending Croatia.
Vukovar did not defend only itself, it defended Croatia, which is why we are proud, but we also have an obligation to express our gratitude to those who gave their lives for Croatia, Sanader said proceeding in a column through the streets of Vukovar towards the town cemetery
He said that anniversaries must not be the only time Croatia remembered Vukovar, adding that officials must visit the town more often.
"This is why it is important to support projects that open prospects for life in Vukovar," the PM said thanking all Croatian counties that were included in the reconstruction of Vukovar on their assistance.
A delegation of the nongovernmental organisation "Women in Mourning", which gathers women from Belgrade and 20 other towns from throughout Serbia, laid wreaths with messages reading "Forgive Us" at the memorial cemetery in Vukovar.
They said they came to Vukovar to ask forgiveness from the families of people killed by Serbian forces 15 years ago and to stress the need for punishing those responsible.
It is with sadness and with a feeling of shame that we remember the tragedy of Vukovar, Women in Mourning said.
The marking of the 15th anniversary of the Vukovar tragedy, which this year is being held under the slogan "Pilgrimage to Croatia's Freedom", started this morning with a commemoration in front of the town hospital.
Participants in the commemorations then proceeded in a column through the streets of Vukovar towards the town cemetery, where state and other delegations laid wreaths and lit candles.
After the wreath-laying ceremonies, a requiem mass for those who were killed or went missing in the war was held by Zagreb Archbishop Josip Bozanic.
According to reports, some 25,000 people from all over Croatia are expected to take part in the commemorations. More than 100 reporters are covering the event.
The battle of Vukovar started on 25 August 1991. Some 1,800 Croatian soldiers fought back much stronger enemy troops for three months, until 18 November, when the defence lines were broken. During the siege some 15,000 people lived in the town, which was hit by 8,000-9,000 shells every day. According to data from the town hospital, 1,642 people were killed and 2,557 wounded in the attacks, while 22,000 Croats and other non-Serbs were sent into exile after the fall of the town.
Five hundred and ten people from Vukovar-Srijem County are still listed as missing.