The embattled Home Secretary insists she will ensure immigration policy is "fair and humane" amid growing calls for her to resign.
"Since appearing before the Select Committee, I have reviewed the advice I was given on this issue and become aware of information provided to my office which makes mention of targets".
Justice Secretary David Gauke told Sky News on Saturday he was confident there was no intention by Ms Rudd to mislead and gave her his backing.
They were brought to the United Kingdom in response to post-war labour shortages in the United Kingdom and given indefinite leave to remain - but those without documents were recently told they needed evidence to continue working, get treatment from the NHS or to remain in the UK. Amber will be missed in many ways.
He called her "the Silver Spoon" in his columns because of her privileged background.
But it was Windrush - and her apparent lack of grip on her department - that ended her tenure at the Home Office, despite a series of U-turns and apologies.
"Outstanding questions remain, and a change of Home Secretary must mean a change in the "hostile environment" policies begun by her predecessor, or it will be meaningless".
And Liberal Democrat MP Layla Moran said: "The Government have no plan and no clue".
"When documents that should be placed in front of a Home Secretary aren't then placed in front of a Home Secretary, that is sad, that is regrettable", he said. "To be frank they are rudderless".
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Her decision to stand down will come as a major blow to Mrs May who publicly declared her "full confidence" in her as recently as Friday.
Rudd will tomorrow make a statement to the House of Commons after facing intense pressure over an allegedly inaccurate statement to Parliament which came amid an ongoing scandal over the treatment of the so-called Windrush generation, a group of British citizens who immigrated from the Commonwealth.
The furor has grown since the Guardian newspaper reported that some people who came to the United Kingdom from the Caribbean in the decades after World War II had recently been refused medical care in Britain or threatened with deportation because they could not produce paperwork proving their right to reside in the country.
When she did respond, in four highly defensive tweets, she apologised once again for the Windrush scandal and said she should have been known about the targets.
THE most delicate balance in British politics is between those who backed Brexit and those who voted against it.
He claimed that targets were "very different" from Ms Rudd's "ambition" to increase the number of illegal immigrants being deported. She continued to say that she was "not aware of any person being removed" and vowed to find out from High Commissioners of the Commonwealth countries. "I accept I should have been and I am sorry that I wasn't".
May accepted Rudd's resignation by letter on Sunday.
Communities Secretary Sajid Javid, whose parents emigrated from Pakistan in the 1960s, said the Government was committed to "put things right".
"This Government has been committed to trying to deal with the injustices in society, some of which matter more to people from ethnic minorities".