WASHINGTON — A lawyer for the Rand Paul campaign has sent a legal notice to TV stations that ran a hawkish attack ad based on Paul's views on Iran, calling the ad defamatory and asking stations to stop showing it.

The letter is an objection to a million-dollar ad buy by a group called the Foundation for a Secure and Prosperous America, led by Republican operative Rick Reed. The ad, which launched in early primary states on the day of Paul's presidential campaign announcement, accuses Paul of supporting President Obama's policies on Iran and of opposing new sanctions.

"The Advertisement attempts to deceive voters regarding Senator Rand Paul's position on U.S.-Iran relations through at least three false statements," writes Paul campaign general counsel Matthew T. Sanderson in the letter dated April 7, which was obtained by BuzzFeed News on Thursday.

The letter advises television stations that they are "not protected from legal liability for airing a false and misleading advertisements sponsored by FSPA" and demands that they "immediately cease airing the Advertisement."

FSPA wrote a letter of response to station managers on Wednesday.

"Senator Paul is free to run his own advertisements trying to explain why he said new sanctions against Iran would be a 'huge mistake,' why he told the Today Show he is 'in favor of negotiations with Iran,' and why he stated it is 'ridiculous to think [the Iranian regime is] a threat to [American] national security,'" Reed writes in the letter. "But it is not appropriate for his campaign to attempt to silence those who oppose his dangerous positions by making baseless threats against your station."

Paul came under criticism this week for appearing testy and impatient in an interview with Savannah Guthrie, who challenged him on statements he has made in the past on foreign policy.

"We believe the ad is misleading, inaccurate and false, in fact Politifact rated it 'Mostly False,'" Paul spokesperson Sergio Gor wrote in an email. "We believe TV stations should be made aware of that."

FSPA is now launching a new ad against Paul, obtained by BuzzFeed News, which uses footage from this week's interviews with Guthrie and with Sean Hannity: