Washington (CNN) -- The U.S. could put its draft resolution on Iran sanctions up for a vote at the U.N. Security Council next week, without the desired support of council members Turkey and Brazil, a senior administration official tells CNN.
The official, who spoke on background because of the diplomatic sensitivity of the issue, said the U.S. does not intend to "wait until everybody is aboard."
In the daily State Department briefing Wednesday, however, department spokesman P.J. Crowley referred to the timing of the vote by saying it would come in June.
"I think you will see this matter come before the Security Council for a vote sometimes this month," Crowley told reporters. He cited President Barack Obama's earlier statement that he wants a vote by the "end of spring."
The U.S. introduced its draft resolution last month. Crowley said he expects annexes, which describe some of technical details of the sanctions, to that draft will be completed within the "next few days."
At the United Nations, the Security Council president, Mexican Ambassador Claude Heller, said the resolution's sponsors want "prompt action." But Heller speculated to reporters it may take perhaps ten days or more for a vote. Lawyers and other experts, he said, have been discussing the resolution and "progress has been made on the text."
The United States is facing significant opposition from Turkey and Brazil on the push for sanctions. The deadly raid by Israeli forces on a flotilla of civilian ships has complicated matters -- especially with Turkey, which had significant numbers of its citizens aboard the flotilla.
Turkey's Foreign Minister, Ahmet Davutolgu, told reporters Tuesday in Washington that Turkey remains opposed to sanctions and was critical of the U.S. for not directly condemning the Israeli attack. In May, the leaders of Turkey and Brazil traveled to Tehran and brokered a nuclear fuel swap deal with Iran. That deal was dismissed by the United States as inadequate.
"Brazil thinks it is counterproductive to discuss sanctions right now" while Iran still has a month to follow through on its side of the nuclear swap deal, a Brazilian official told CNN. The official spoke on background because of the sensitivity of the issue. Under that agreement, Iran said it will ship 1,200 kilograms (about 2,640 pounds) of low-enriched uranium out of the country to Turkey for safe-keeping. In exchange, it would receive nuclear fuel rods needed for an Iranian reactor that produces medical isotopes.
The Brazilian official called the deal "a good starting point" and a "confidence-building measure."
The State Department spokesman said the deal still does not address the problem that Iran continues to enrich uranium.
CNN's Richard Roth contributed to this report.