Obama will sign Iran sanctions bill passed by Senate
© Getty Images

The Senate easily passed an extension of an Iran sanctions law on Thursday, sending the legislation to President Obama’s desk.

Senators voted 99-0 to approve a 10-year extension of the Iran Sanctions Act, which includes penalties against Iran’s banking, defense and energy sectors. The law was set to expire at the end of the year.

Sen. Bernie SandersBernard (Bernie) SandersSchumer: Franken should resign Franken resignation could upend Minnesota races Avalanche of Democratic senators say Franken should resign MORE (I-Vt.) didn't vote.

Obama is expected to sign the legislation, a White House official said Thursday, ending weeks of uncertainty about a possible veto. 

The official said the administration has determined the measure does not violate the Iran nuclear agreement, meeting a condition had Obama set to earn his signature. 

Lawmakers argue the sanctions extension is needed as a failsafe in case Iran breaks its commitment under the landmark pact reached last year. 

Under the deal, Iran agreed to curtail its nuclear program in exchange for the United States and other countries lifting economic sanctions.

"The practical effect is the Iran nuclear agreement depends on our resolve, on our commitment to... stop a nuclear-armed Iran by using sanctions and other means if necessary," said Sen. Richard Blumenthal (D-Conn.), who supported the Iran deal.

Even though Obama will sign the measure into law, the White House said it views it as unnecessary, arguing the administration has broad latitude to punish Iran if it violates its commitments to the deal. 

Senate Republicans, including Foreign Relations Committee Chairman Bob CorkerRobert (Bob) Phillips CorkerFormer Dem Tenn. gov to launch Senate bid: report McConnell 'almost certain' GOP will pass tax reform Former New Mexico gov: Trump's foreign policy is getting 'criticized by everybody' MORE (R-Tenn.), initially wanted to pass the extension as part of a broader bill that would also bolster sanctions against Iran for a string of ballistic missile tests.

But Democrats signaled early that they wouldn't support anything besides a "clean" extension of the law.

Senate Majority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellGOP strategist donates to Alabama Democrat McConnell names Senate GOP tax conferees Brent Budowsky: A plea to Alabama voters MORE (R-Ky.) indicated Thursday the extension would give President-Elect Donald TrumpDonald John TrumpHouse Democrat slams Donald Trump Jr. for ‘serious case of amnesia’ after testimony Skier Lindsey Vonn: I don’t want to represent Trump at Olympics Poll: 4 in 10 Republicans think senior Trump advisers had improper dealings with Russia MORE and a GOP-controlled Congress flexibility as they review Obama's Iran policies next year. 

“These authorities should remain in place as we address how best to deal with Iranian missile tests, support to Hezbollah and the Syrian regime," he said.

The extension easily passed the House last week in a 419-1 vote, but Obama had faced external pressure to reject the legislation.

Ayatollah Ali Khamenei, Iran's supreme leader, warned last week that extending the sanctions law would constitute a violation of the nuclear deal.

"The most recent of them is the 10-year extension of the sanctions. If these sanctions are extended, it will surely constitute a violation of the [Joint Comprehensive Plan of Action] and they should know that the Islamic Republic will definitely react to it,” he said. 

Jordan Fabian contributed. This story was updated at 3:07 p.m.