Britain's party leaders have been warned against inciting racial tensions during the election campaign.
Mr Phillips said political parties need to 'calm down'
The head of the Commission for Racial Equality, Trevor Phillips, told the Times politicians needed to "reduce the temperature" on political debates.
His comments follow reports around the country of racist violence, including attacks on traveller sites.
He said politicians needed to "take a step back" and realise what their words "may do to people on the ground".
Mr Phillips said he is worried that the atmosphere is "sour, fractious and brittle", and that there are signs of pre-election debates causing racial hostility.
"I can't give you survey evidence but we know what's happening in schools. We know what's happening in factories and so on," he told the newspaper.
He said the commission had received reports of racist violence, intimidation and "mob rule".
"I don't like what I'm hearing," he said. "I think it is becoming ugly".
Mr Phillips used the examples of the controversial Labour poster, in which Michael Howard was said to look like Fagin, playing on his Jewish ancestry, and the Tory immigration billboards.
His comments also follow the launch of the Conservative manifesto, which includes pledges of "controlled immigration" and new powers to local councils to deal with illegal traveller sites.
But Mr Phillips said he did not think the parties were intentionally attempting to stir up racial hostility.
He said political parties needed to realise the effect their words may be having on the general public, and "ensure debate remains rational".
"What they've all got to understand is what they intend and what they think they are saying is not necessarily what other people are hearing," he said.
So far, Labour have announced they will introduce tougher rules on settlement and increase deportation to reduce asylum numbers.
They would also bring in an electronic register of all crossing borders and skills-based points system for permanent immigrants.
The Liberal Democrats say they will allow asylum seekers to work so don't rely on benefits and introduce a quota for immigrant workers from outside EU.