Nuclear talks between Iran and world powers have only given the Islamic republic more time to pursue its quest for a nuclear weapon, a senior Israeli official told Agence France Presse on Saturday.

Two days of talks on Tehran's controversial atomic drive with the five permanent members of the U.N. Security Council -- the United States, China, Russia, Britain and France -- plus Germany ended on Wednesday.

The leaders of Iran and the United States competed on Tuesday with sharply worded messages for the start of the Iranian new year that highlighted global tensions over Tehran's controversial nuclear program.

Iran's supreme leader, Ayatollah Ali Khamenei, warned in a speech broadcast live on state television: "We have said that we do not have atomic weapons and we will not build any.