DUBAI, (Reuters) – Iran’s foreign ministry said Saturday that U.S. officials had tried to resume nuclear talks last month. But he stressed Washington should first free $10 billion in Tehran’s frozen money as a gesture of goodwill.

Iran rejected talks with the United States and indirect talks to revive a 2015 nuclear agreement aimed at preventing Iran’s development of a nuclear weapon were stopped in June.

State television reported that the United States attempted to reach out to Iran through intermediaries from the United Nations.

Iran is unable, because of U.S. sanctions, to get tens or billions in assets from foreign banks. This has been due primarily to Iran’s oil and gas exports.

The minister stated that the Americans attempted to reach us via different channels (at U.N. General Assembly in New York), and that if America’s intentions were serious, then they needed serious evidence… by releasing at minimum $10 billion of block money.

Amirabdollahian stated in a TV interview that “they aren’t willing to release $10 billion belonging the Iranian nation to allow us to say that the Americans once considered the interests the Iranian nation in the past few decades,”

Western countries have called for Iran to return negotiations. They claim that Iran’s nuclear program has advanced well beyond any limits established by the deal.

Amirabdollahian stated that Iran will “soon” return to the Vienna-stalled nuclear negotiations, but declined to specify a date.

Tehran claims its nukes are possible to reverse if Washington removes all the sanctions. Both Western and Iranian officials said that many issues need to be solved before the agreement can be revived.