Jean Asselborn, Luxembourg's Foreign Minister | Andreas Gebert/Getty Images Luxembourg: US-Iran tensions risk causing ‘giant refugee wave’ Tehran has said it will exceed uranium enrichment levels agreed under 2015 Iran nuclear deal as of Sunday.

Iran should refrain from pursuing its uranium enrichment plans and escalating tensions with the United States, Luxembourg's foreign minister, Jean Asselborn said, warning that deteriorating relations could trigger a "giant refugee wave."

Tehran announced last month it would exceed uranium enrichment levels agreed under the 2015 Iran nuclear deal — the Joint Comprehensive Plan of Action (JCPOA) — as of Sunday. It claims European countries have not done enough to keep the deal alive and relieve Iran from crippling U.S. economic and financial sanctions.

Highly enriched uranium can be used to build nuclear weapons.

"According to the International Atomic Energy Agency in Vienna, Iran has so far always complied with the agreement. On the other hand, I can only warn Iranians not to start enriching uranium beyond what is allowed this Sunday," Asselborn told German newspaper Welt am Sonntag.

Asselborn warned that exceeding the agreed limit agreed in the nuclear deal would not only lead to a deterioration of relations between Iran and the EU, but could also further escalate tensions with the U.S.

Relations between Tehran and Washington have soured in recent weeks after Iran shot down an U.S. Navy surveillance drone and was accused by Washington of being responsible for attacks on two tankers in the Gulf of Oman — a charge Tehran denies.

If the situation between Washington and Tehran continues to escalate, the European Union is likely to be affected by the fallout, Asselborn warned.

"There is a danger that 3 million Afghans living in the country will leave Iran," he said. "Most of them are unlikely to return to Afghanistan because of the security situation, but will go to Turkey and then to Europe."

"There is a risk of a giant wave of refugees posing major challenges to Europe," he added.

Asselborn also said it had been a "total misstep" by U.S. President Donald Trump to withdraw from the nuclear treaty last year.