Romania is for the first time holding a Holocaust commemoration day for the hundreds of thousands of Romanian Jews who were murdered during World War II.
Ion Iliescu (centre) said Romania's wartime leaders took part 'with zeal'
The Romanian government denied that a Holocaust took place on its territory until last year, when its stand led to a diplomatic row with Israel.
The commemorations included a special session of parliament and a ceremony at Bucharest's main synagogue.
President Ion Iliescu said young generations had to know the truth.
Many of Romania's Jews and members of other minorities, including gypsies, died in death camps located in the Transdniester region, now part of neighbouring Moldova.
Others were killed in pogroms - in Bucharest and other towns - or in death trains.
The Encyclopaedia of the Holocaust says that about 420,000 of Romania's 750,000-strong Jewish community died - including 100,000 deported to Auschwitz from areas of the country then under Hungarian rule.
The deportations were ordered by Romania's wartime leader, Marshal Ion Antonescu, on 9 October 1941.
Holocaust Day would have been marked this year on 9 October, but it was moved to the 12th, to avoid clashing with a Jewish holiday.
"The horrible tragedy of the Holocaust was possible due
to the complicity of leaders of the state's institutions
... those who executed, often with a lot of zeal, the
orders of Marshal Antonescu," Mr Iliescu told Tuesday's joint session of the two houses of parliament.
Romania denied any Holocaust on its territory until last year
"Such a tragedy must not be repeated."
During Romania's communist era, the public was told that Germans were the sole perpetrators of the Holocaust.
Antonescu was regarded as a war criminal who merely followed Hitler's orders.
However, he was held up as a hero by some Romanian nationalists after the country gained independence, because he fought a Soviet invasion in 1940.
Last year's row with Israel came after the government suggested there was no Holocaust within Romania's borders.
It later backed down, saying that administrations between 1940 and 1945 were "guilty of serious war crimes".
A committee, headed by Nobel Peace Prize laureate and
Holocaust survivor Elie Wiesel, was set up to study the Romanian Holocaust and publish its conclusions.
Its report is expected soon.
"Neglecting the truth for 60 years was a tragedy. Finally
the government recognises there was a Holocaust in this
country," the Chief Rabbi of Romania, Menachem Hacohen, said on Monday.
About 6,000 Jews now live in the country.