India's Prime Minister Manmohan Singh has apologised in parliament to the Sikh community for the 1984 riots in which 3,000 Sikhs were killed.
Manmohan Singh urged MPs not to make political capital
"I bow my head in shame for what has happened," he said.
His comments came after a government inquiry this week said some Congress party leaders at the time had incited mobs to attack Sikhs.
One Indian minister has resigned and another politician on Thursday quit as a development board chairman in Delhi.
Mr Singh, the current Congress premier and the first Sikh to hold the top post, told parliament: "What took place in 1984 is a negation of what is enshrined in our constitution and on behalf of my country I bow my head in shame for what has happened."
He said: "We cannot undo the past but we can build a better future."
The riots were sparked by the assassination of PM Indira Gandhi by her Sikh bodyguards.
The 339-page inquiry report was tabled in parliament on Monday.
The report, by retired Supreme Court judge GT Nanavati, was the ninth inquiry commission into the riots, and was set up in 2000 by the then governing Bharatiya Janata Party (BJP) which is now in opposition.
The inquiry said that accounts from witnesses and victims of the rioting indicated that "local Congress leaders and workers had either incited or helped the mobs in attacking the Sikhs".
It found "credible evidence" against Jagdish Tytler, the minister for expatriate Indians, and recommended further investigation into his role.
Mr Tytler offered his resignation on Wednesday and it was accepted on Thursday on the recommendation of Mr Singh.
Mr Tytler denies wrongdoing and said he was resigning to work to clear his name.
On Thursday, another Congress MP whose role was questioned by the inquiry, Sajjan Kumar, resigned as chairman of the state-run Delhi Rural Development Board.
In parliament, Mr Singh urged MPs not to make political capital from the inquiry.
Sikhs have protested angrily over the findings
"Let us not create a situation or use loose language which will give a handle to those forces which are inimical to our country's unity, integrity and cohesion," he said.
"It is no service to the Sikh community or to our nation."
However, widows of some of those killed in the riots have protested on the streets of Delhi, demanding Mr Singh's resignation.
The BJP has repeated its calls for prosecutions.
The Indian media have said that despite all the commissions of inquiry, there has been scant justice for the victims' families.
The Indian Express said: "The fact that not one of those who masterminded or spearheaded this carnage has had to face punishment will remain an affront to the nation."