Solana echoed U.S. Secretary of State Condoleezza Rice, who suggested that Iran "change tactics," the Iranian broadcaster Alalam reported.
"I hope Iran to show more flexibility on its nuclear stance to help create grounds for official talks," Solana told reporters as he arrived in Madrid. "We spare no efforts in re-launching the negotiations."
Iran maintains that its nuclear enrichment program is an effort to develop nuclear energy for peaceful purposes.
"There is no possible path for the suspension of the enrichment of uranium," Mohammad Ali Hosseini, a spokesman for the Iranian Foreign Ministry, said Thursday.
As talks began, the International Atomic Energy Agency, the U.N. nuclear watchdog, released a report that said that Iran has continued its nuclear program, defying a Security Council sanctions resolution. The IAEA also said that its inspectors have been denied access to critical areas in Iran, Voice of America reported.