World powers trying to end a standoff over Iran's nuclear program are weighing whether to meet next week to discuss tougher measures, a European Union official said Thursday as Russia reiterated its reluctance to agree to new sanctions.

The foreign minister of Sweden, which holds the EU's rotating presidency, expressed concern that Iran's internal strife was preventing it from focusing on international negotiations.

Political directors of the five permanent members of the Security Council _ Britain, China, France, Russia and the United States _ plus Germany may meet next week, according to the EU official, who spoke on condition of anonymity because the meeting had not yet been arranged. The official said the site of the meeting was still under discussion.

In Washington two U.S. officials said that the Obama administration expects the group _ known as P5+1 _ to meet at the end of next week.

EU leaders said they would support further U.N. sanctions against Iran unless Tehran starts cooperating over its nuclear program.

"Iran's persistent failure to meet its international obligations and Iran's apparent lack of interest in pursuing negotiations require a clear response, including through appropriate measures," said a draft statement, obtained by The Associated Press, being discussed by EU leaders at a summit in Brussels.

At the United Nations, the United States, Britain and France warned Thursday that Iran risks increased sanctions unless it immediately complies with a series of Security Council resolutions regarding its nuclear program.

Russia's top foreign ministry spokesman said Moscow remains opposed to sanctions on Iran over its refusal to halt its uranium enrichment program. Andrei Nesterenko said at a televised briefing on Thursday that "the language of sanctions is not our language."

President Dmitry Medvedev said after a meeting with President Barack Obama in September that sanctions are sometimes inevitable, but Russian officials have later backtracked from that remark.

Prime Minister Vladimir Putin, who is widely believed to continue calling the shots, said in October that the talk about sanctions could thwart negotiations with Iran. Ever since, Russian diplomats have insisted on the need to focus on diplomatic means.

Swedish Foreign Minister Carl Bildt said the EU was trying to bring all parties to the negotiating table.

"But at a time when it is much easier to engage with Iran because the Americans are on board, Iran itself is in a state of turmoil that makes this exercise much more difficult than it would have been otherwise," he said.