The White House said on Monday that the newly-reached Iran nuclear fuel swap deal would be a positive step, but the United States continues to have serious concerns over Iran.

The White House said in a statement that it acknowledges the efforts made by Turkey and Brazil, which have helped to broker the nuclear fuel swap deal.

"Given Iran's repeated failure to live up to its own commitments, and the need to address fundamental issues related to Iran's nuclear program, the United States and international community continue to have serious concerns," said the statement.

The statement said the deal would be a positive step, but Iran' s announcement on Monday to continue its 20-percent enrichment activities is "a direct violation" of UN Security Council resolutions.

The White House also pledged that the United States will " continue to work with the international partners, and through the UN Security Council," on the Iranian nuclear issue.

"We remain committed to a diplomatic solution to the Iranian nuclear program, as part of the P5+1 dual track approach, and will be consulting closely with our partners on these developments going forward," the White House said in the statement.

The "dual track approach" refers to diplomacy of engagement and sanctions. The P5+1 refers to the five permanent members of the UN Security Council -- China, the United States, Britain, France and Russia -- plus Germany.

Iran signed an agreement with Turkey and Brazil in Tehran on Monday by which it will ship most of its low enriched uranium to Turkey in exchange for the 20-percent uranium fuel needed for its Tehran reactor.

Iran agreed to a draft proposal whereby it will send some 1,200 kg of its 3.5-percent enriched uranium over to Turkey in exchange for a total of 120 kg 20-percent uranium needed for a medical research reactor.

The International Atomic Energy Agency proposed last autumn that Iran takes its uranium of 3.5-percent purity to other countries, where it can be processed into high-enrichment uranium of 20 percent. The processed high-enrichment uranium will be then used as fuel for nuclear reactors and for medical purpose.

Iran had rejected the deal, insisting a simultaneous swap of the fuel on its soil.