Washington, DC - US President Donald Trump passed up a chance to derail the nuclear deal with Iran on Wednesday, a move analysts said reflected business interests at home and diplomatic relations abroad.

During Trump's election campaign he vowed to "rip up" the nuclear agreement with Tehran if elected, calling it "the worst deal ever".

Trump had until Thursday to extend a sanctions waiver on Iran, and the US state department announced a day earlier it would be signed, meaning old sanctions wouldn't be re-imposed and the nuclear deal will continue - at least for now.

"We are communicating to the US Congress that the United States continues to waive sanctions as required to continue implementing US sanctions-lifting commitments," a State Department statement said.

READ MORE: Analysis: What does the Iran nuclear deal mean?

However, the department also announced the imposition of new unrelated sanctions against Iranian defence officials and an Iranian "entity". It also pledged to continue reviewing the nuclear deal with withdrawal still possible.

"This ongoing review does not diminish the United States' resolve to continue countering Iran's destabilising activity in the region, whether it be supporting the Assad regime [in Syria], backing terrorist organisations like Hezbollah [in Lebanon], or supporting violent militias that undermine governments in Iraq and Yemen.

"And above all, the United States will never allow the regime in Iran to acquire a nuclear weapon," the statement said.

Iran agreed under the 2015 nuclear deal to curtail its nuclear programme in exchange for a lifting of sanctions that had crippled its economy.

Along with the P5+1 (five permanent UN Security Council members plus Germany), the Obama administration touted the nuclear deal as a crucial move towards detente with Iran and regional peace.

The US president must review and sign the sanctions relief waiver every 120 days. After taking office in January, Thursday was Trump's first opportunity to roll it back.

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Lawrence Korb, a senior fellow at the Center for American Progress and former US assistant secretary of defence, said the Trump administration's continuation of the nuclear deal is similar to the situation with China.

Trump slammed China's "unfair" trade policies throughout his election campaign, but once in office he quickly smoothed things over with Chinese President Xi Jinping.

On Iran, Korb noted the importance of the $6bn Boeing deal with Tehran that could mean the creation of 18,000 American jobs.

"Trump is a businessman after all," Korb told Al Jazeera. "Again its rhetoric verses policy. I was the assistant secretary of defence under Ronald Reagan who denounced the 'evil Soviet Empire' - and then was ready to give up our nuclear weapons."

Phyllis Bennis, a fellow at the Washington DC-based Institute for Policy Studies, said the danger threatening the nuclear deal is the imposition of new sanctions and the US government's belligerent language towards Iran.

"That kind of language fuels the hardliners. It is a gift to the hardline elements in the Iranian political scene," Bennis told Al Jazeera.

READ MORE: Obama: Abandoning Iran nuclear deal could mean war

Europe's leaders are quickly moving forward on economic normalisation with Iran, and scuttling the nuclear deal would have wide-ranging diplomatic repercussions with major allies, she said.

"No question Europe would be furious. This is not a bilateral deal between Tehran and Washington, it's with five other countries along with the US… So this kind of unilateralism will infuriate every European country," said Bennis.

Since its implementation, the nuclear deal has brought positive results, she added.

"It has reduced the threat of war … and it improves the lives of Iranians by reducing at least some of the economic sanctions that have crippled so much of the country's economy."