BRUSSELS, Nov. 2 (Xinhua) -- The European Union (EU) and it's troika (France, Germany and Britain) on Friday jointly showed their deep regret on Washington's further re-imposition of sanctions against Iran, vowing to protect European economic operators engaged in legitimate business with Tehran.

The U.S. administration announced Friday it will snap back sanctions on Iran that had been lifted under the historic 2015 Joint Comprehensive Plan of Action (JCPoA).

While announcing the sanctions, the White House blasted the Iran nuke deal again, saying it was "disastrous" and "unacceptable".

But for the Union, the JCPoA is a key element of the global nuclear non-proliferation architecture and of multilateral diplomacy.

"It is crucial for the security of Europe, the region, and the entire world," said the four parts in a joint statement co-signed by High Representative of the Union for Foreign Affairs and Security Policy Federica Mogherini and financial as well as foreign ministers of France, Germany and Britain.

In May, U.S. President Donald Trump announced Washington's withdrawal from the landmark Iran nuclear deal. Since then, the Trump administration has slapped a number of sanctions on Iran.

"The JCPoA is working and delivering on its goal. The International Atomic Energy Agency (IAEA) has confirmed in 12 consecutive reports that Iran is abiding by its commitments under the Agreement. We expect Iran to continue implementing all its nuclear commitments in full, as set out by the JCPoA," said the joint statement.

Hours earlier, the White House said the sanctions, to fully take effect on Nov. 5, would be "the toughest" and "unprecedented", targeting many of Iran's "critical sectors" including energy, shipping, shipbuilding and finance.

By contrast, the EU and its troika in the statement defended its aim to "protect European economic operators engaged in legitimate business with Iran, in accordance with EU law and with UN Security Council resolution 2231".

"As parties to the JCPoA, we have committed to work on, inter alia, the preservation and maintenance of effective financial channels with Iran, and the continuation of Iran's export of oil and gas. On these, as on other topics, our work continues, including with Russia and China as participants to the JCPoA and with third countries interested in supporting the JCPoA," said the statement.

"These efforts have been intensified in recent weeks, particularly those underpinning the European initiative to establish a Special Purpose Vehicle on which we are proceeding with work to set up. This will enable continued sanctions lifting to reach Iran and allow for European exporters and importers to pursue legitimate trade," said the statement.

As a legal entity, the Special Purpose Vehicle is a payment system to bypass US sanctions against Iran. The move is likely to deepen the rift between the U.S. and Europe.

U.S. Secretary of State Mike Pompeo said earlier that he was "disturbed and indeed deeply disappointed" at the planned special payment system.

"This is one of the most counterproductive measures imaginable for regional global peace and security," he told a conference.

Despite Pompeo's opposition, Europe vowed to do more to "assist and reassure economic operators pursuing legitimate business under EU law."

"Our collective resolve to complete this work is unwavering," read the statement.

"We remain committed to implementing the JCPoA as a matter of respecting international agreements and of our shared international security, and expect Iran to play a constructive role in this regard," said the statement.