Istanbul, Turkey (CNN) -- Turkey's top diplomat called this week's agreement for an Iranian nuclear swap one of the most important diplomatic decisions in the 30-year history of the Islamic Republic of Iran.
The deal, which was reached after 18 hours of negotiations between the foreign ministers of Iran, Brazil and Turkey on Sunday, calls for Iran to hand over nearly half of its estimated supply of low-enriched uranium to Turkey.
Within a year, Western governments and the International Atomic Energy Agency would be expected to exchange 1,200 kilograms of 3.5-percent enriched uranium for 120 kilograms of 20 percent medium-enriched uranium.
At a press conference in Istanbul, Foreign Minister Ahmet Davutoglu congratulated Iran, Turkey's eastern neighbor, for showing "flexibility, political will and a vision for the future."
Davutoglu challenged the United States, Britain and Russia, which have all voiced skepticism since the deal was signed in Tehran, Iran, on Monday by ministers from Brazil, Turkey and Iran.
Discussing sanctions will "spoil the atmosphere" and escalate the situation, Davutoglu said. "Iranian public opinion is very sensitive on this issue ... there will be, I'm sure many criticisms in Iran. Therefore each side should now have a positive approach ... rather than focusing on mutual suspicion, skepticism, mutual threats, sanctions or other options."
Last fall, Iran backed out of a similar agreement with Western governments to swap nuclear fuel in an effort to limit its attempts to enrich uranium. Turkey had been proposed by the International Atomic Energy Agency as a possible location for the international nuclear swap.
On Tuesday, the spokesman for Iran's foreign ministry suggested Western governments may have been quick to jump to conclusions and criticism in the wake of Monday's agreement.
"Maybe it was unexpected for them," said Ramin Mehmanparast at a briefing in Tehran. "There was little time to think about the declaration, and we hope they take the time to read it and understand it."
On Monday, within hours of the signing of the nuclear swap agreement, the Iranian government announced it would continue enriching some uranium to a level of 20 percent.
One Turkish diplomat in Ankara called the announcement "unfortunate." The White House later issued a statement calling this a violation of U.N. Security Council resolutions, saying the Iranian government "must demonstrate through deeds -- and not simply words -- its willingness to live up to international obligations or face consequences, including sanctions."
At his press conference on Tuesday, Turkey's foreign minister said he briefed Russian Foreign Minister Sergei Lavrov and U.S. Secretary of State Hillary Clinton by telephone on the nuclear swap agreement.
Davutoglu then credited U.S. President Barack Obama's "multilateral diplomacy" for paving the way towards enabling Brazil and Turkey to work out this week's deal with Iran.
And he described Turkey's motive for working towards a nuclear deal with its eastern, Iranian neighbor:
"We don't want war. We don't want tensions. We don't sanctions in our region. We don't want problems," Davutoglu said. "We want peace, stability, security."
Iran is expected to deliver the agreement in writing to the IAEA, the U.N.'s nuclear watchdog, within the next seven days.