U.S. President Barack Obama warned on Wednesday that a block of the Iran nuclear deal by U.S. lawmakers would accelerate Iran's path to a nuclear weapon.

Obama spoke at American University amid a furious lobbying effort in Congress to secure the enough support to ensure survival of the deal, which was reached July 14 between Iran and six world powers.

Obama said Iran will be more capable of building a nuclear weapon if the deal is blocked and a military solution will only drive its nuclear development deeper underground.

Opponents of the deal say it does not go far enough to ensure that Iran will never be able to develop a nuclear weapon and argue that lifting sanctions on Iran will only empower it to do so.

Obama said many of the criticisms, which are made widely by Republicans in Congress, can be attributed to "knee-jerk partisanship" and spread false fears about the deal, which lawmakers are set to vote on next month.

"I know it's easy to play on people's fears, to magnify threats... but none of these arguments hold up," Obama said.