WASHINGTON: Secretary of State John Kerry said Friday that if the US Congress disapproves of the Iranian nuclear deal, it would undermine President Barack Obama’s ability to act throughout the world.

It would be a “repudiation of President Obama’s initiative and a statement that when the executive department negotiates, it doesn’t mean anything anymore because we have 535 Secretaries of State,” Kerry said, referring to the number of members of both houses.

Kerry defended the nuclear deal the US and five other world powers negotiated with Iran at the Council on Foreign Relations in New York, saying that the deal struck last week in Vienna is the only alternative to military action and must be tested if diplomacy is to succeed.

In a reprise of his testimony Thursday before the Senate Foreign Relations Committee, Kerry said the agreement is the best way to prevent Iran from developing an atomic weapon. If Congress rejects the deal, he said Iranian hard-liners would speed ahead with their nuclear program and the international sanctions regime would collapse.

Kerry said it would be a huge mistake if Israel decided to take unilateral military action against Iran over its nuclear program in the future. Kerry was asked in an NBC "Today" show interview if the deal would make it more likely that Israel might attempt a military or cyber attack on Tehran.

"That'd be an enormous mistake, a huge mistake with grave consequences for Israel and for the region, and I don't think it's necessary," Kerry said.

Iran’s foreign reserves total between $115 billion and $125 billion, including assets in its sovereign wealth fund, its industry minister said.