One senator who attended the meeting Wednesday said Obama's case was "one of the most powerful arguments" about the issue he had ever heard from the president, CNN reported.
"They discussed Iran and the president made the case for why new sanctions legislation now would hurt us," a senior administration official told CNN.
A six-month interim agreement with Iran begins Monday. Under terms of the deal, Iran must dismantle or freeze some of its nuclear program and allow more international inspections in return for limited relief from international sanctions.
If all goes as planned, negotiators from Iran, the United States, France, Russia, China, Britain and Germany will seek a broader agreement to prevent Tehran from developing a nuclear weapon.
However, pro-Israel members of Congress want additional sanctions against Iran that would take effect if the talks break down.
"The president did speak passionately about a way to seize this opportunity that we have," said Sen. Jeff Merkley, D-Ore., after the meeting. "If Iran isn't willing in the end to make the decisions necessary to make it work, he'll be ready to sign a bill to tighten those sanctions. But we've got to give this six months."
Merkley told Politico the mood generally was "quite supportive" of Obama's position.
The meeting lasted for more than two hours, Politico said. Besides discussing Iran, those attending the meeting said Obama discussed the need to raise the minimum wage, improve education, immigration and keep the Senate under Democratic control.