Iran's foreign minister said Friday that efforts to free Western hostages in Lebanon were at a "dead end" because their captors have gotten nothing for releasing captives in the past, Tehran radio reported.

Repeating previous conditions for the release of the hostages, Foreign Minister Ali Akbar Velayati said that hundreds of Arab prisoners must be freed by Israel and its proxy, the South Lebanon Army militia.Velayati also said relations between Tehran and Washington, severed in 1979, could improve only if billions of dollars of Iranian assets frozen in the United States were released.

But he did not link that issue to the hostages. Iran denies any involvement with the kidnappers, saying it only has influence with them.

The radio, monitored in Nicosia, said Velayati was speaking in an interview with two U.S. television networks.

Dutch Foreign Minister Hans van den Broek, who returned from a visit to Tehran on Thursday, said the Iranian government was working to secure the release of Western hostages.

"Iran is ready and already making efforts" to win freedom for the captives, he said.

Six Americans and seven other Westerners are missing and believed held hostage by pro-Iranian Shiite Muslim fundamentalist groups in Lebanon.