After Paris warned that new sanctions against Teheran remained an option despite the likelihood of negotiations with Iran, French President Nicolas Sarkozy maintained that the Islamic republic was still working on a nuclear weapons program. "It is a certainty to all of our secret services. Iran is working today on a nuclear [weapons] program," Sarkozy told lawmakers from his UMP party on Tuesday, according to Press TV. "We cannot let Iran acquire nuclear" weapons because it would also be a threat to Israel, he added. French Foreign Ministry spokesman Bernard Valero had warned that Iran must make "concrete gestures" at the long-awaited discussions. He said the sanctions option remained on the table in case Teheran makes "an error of choice." "It is up to Iran to restore international confidence ... and show it is ready to seriously discuss its sensitive activities," Valero said at a press briefing. Earlier, Sarkozy and US President Barack Obama discussed ways to bring Iran "into compliance" with UN resolutions on its nuclear program, Agence France Presse quoted the White House as saying. "The two leaders discussed the status of diplomatic efforts to bring Iran into compliance with its international obligations on its nuclear program," according to a released after Obama and Sarkozy spoke over the telephone. Also Tuesday, EU foreign policy chief Javier Solana said that talks on Iran's nuclear program would likely be held in Turkey, and full US participation may lead to progress in the negotiations. Casting aside conditions the Bush administration had set for talks, President Barack Obama's White House is pressing for progress after years of little movement on Iran's nuclear program. "The Americans will be present in a formalized manner. This is new," Solana said, referring to the meeting scheduled for October 1. "I think that has to be evaluated positively by the Iranians." Solana said the meeting could help resolve the standoff over the Islamic republic's refusal to freeze uranium enrichment and heed other UN Security Council demands. The talks will be the first since a 2008 session in Geneva foundered over Iran's refusal to discuss enrichment. The US has announced that Undersecretary of State for Political Affairs William Burns - who was at the Geneva talks as an observer - would again represent the US But this time, EU officials said, Burns will be a full participant in the upcoming meeting, which will also include representatives of Britain, France, Russia, China and Germany. In Washington, US Secretary of State Hillary Rodham Clinton said the American delegate to the talks would insist on discussing Iran's nuclear program. "I think it is important to underscore that we have made clear to the Iranians that any talks we participate in must address the nuclear issue head on," Clinton told reporters at the US State Department. "It cannot be ignored. Iran says it has a number of issues that it wishes to discuss with us but what we are concerned about is discussing with them the questions surrounding their nuclear program and ambitions."