Iran will have the capability to develop nuclear weapons in three to eight years, Mohamed ElBaradei, the head of the United Nations nuclear watchdog, warned Thursday. "If Iran wanted to go for nuclear weapons, it would not be before the end of this decade or the middle of next decade, in other words three to eight years," DPA QUOTED ElBaradei as saying in Luxembourg. ElBaradei, who heads the Vienna-based International Atomic Energy Agency (IAEA), said Iran was expanding its knowledge and its capacity to enrich uranium. This was especially worrying because it was happening at a time when the IAEA was not in a position to undertake "full and robust inspections" in Iran, he said. "If we continue in that direction, we would end up with a major confrontation, we would reduce the possibility of a peaceful resolution of the issue," ElBaradei warned. The IAEA chief appealed to Tehran to suspend uranium enrichment activity as a "confidence-building measure." But he also urged the US and European countries to do their best to engage Iran in a wide-ranging dialogue focusing on Tehran's economic and technology concerns. "We need to have a comprehensive settlement" including discussions on security, said ElBaradei. The IAEA head called for a "multiple time-out" under which Iran would suspend uranium enrichment while the United Nations put the brakes on sanctions against Tehran. Negotiations were needed because the current international stalemate with Iran was not acceptable given growing concerns about the nuclear proliferation, he cautioned. ElBaradei repeated an IAEA warning earlier this week that its knowledge of Iran's nuclear programme was "deteriorating." Tehran denies that it is building nuclear weapons, arguing that its nuclear programme is for civilian use only. The UN Security Council tightened sanctions against Iran in March this after Tehran continued to defy international demands to halt uranium enrichment. Tehran, in turn, decided to limit its co-operation with the IAEA although inspectors from the agency still regularly visit Iran's atomic facilities under the nuclear Non-Proliferation Treaty. Another UN deadline for Iran to comply with its demands runs out on Thursday.