Respect MP George Galloway has vowed not be silenced after he was interviewed under caution by police investigating his declaration that Bradford was "an Israel-free zone".
West Yorkshire Police received more than 300 complaints about a speech earlier this month in Leeds in which he said Israelis were not welcome in the city where he has a constituency.
Detectives travelled to London to speak to him and he did so voluntarily under caution, and is understood to have denied being anti-Semitic.
Mr Galloway said: "This is an absolute and despicable attempt to curb my freedom of speech by people who appear to be quite happy about the indiscriminate murder of Palestinians in Gaza.
"I won't be silenced, I will keep speaking out against horrendous injustice."
He is understood to believe no prosecution for inciting racial hatred will follow his comments. He is thought to have told police that Israel was not a race.
The Crown Prosecution Service will decide whether any charges should be made
District commander for Leeds Chief Superintendent Paul Money said: "A 59-year-old man has been interviewed under caution voluntarily following complaints made about the content of a speech given in Leeds earlier this month.
"Once inquiries are completed, the matter will be referred to the Crown Prosecution Service for their consideration."
Film of his speech shows Mr Galloway standing in front of a Palestinian flag saying: "We have declared Bradford an Israel-free zone.
"We don't want any Israeli goods. We don't want any Israeli services.
"We don't want any Israeli academics coming to the university or college.
"We don't even want any Israeli tourists to come to Bradford, even if any of them had thought of doing so.
"We reject this illegal, barbarous, savage state that calls itself Israel. And you have to do the same."