Leading Republicans will do their utmost to prevent any nuclear deal with Iran coinciding with pro-Israel lobby groups, they announced Wednesday, by investing tens of millions of dollars in a national television advertising campaign to derail the agreement.

The move came as Congress began a 60-day review of the deal between Iran and world powers, which would rein in Iran’s nuclear program in return for sanctions relief, leading up to a Sept. 17 deadline.

Republican U.S. House of Representatives Speaker John Boehner on Wednesday labelled it “a bad deal,” claiming it “threatens the security of the American people,” threatening to “do everything possible to stop it."

The pro-Israel advertisement, currently being aired in various states across the country, was backed by lobbyist groups such as the Citizens for a Nuclear Free Iran and the powerful American Israel Public Affairs Committee.

During the first half of 2015, AIPAC spent around US$1.6 million on congressional lobbying efforts to introduce legislation giving lawmakers the ability to review an Iran nuclear deal, which the group strongly opposes.

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The US$1.67 million AIPAC spent so far this year is more than the group has ever spent on direct lobbying during a six-month period, according to the Senate Office of Public Records database,

According to the Center for Responsive Politics, which tracks political money, the top congressional recipients included such Israel allies as House Foreign Affairs Chairman Ed Royce of California, who received US$32,500, and Democrat Senator Richard Blumenthal, who received $29,900.