The United States has shown flexibility on allowing Iran to maintain limited peaceful nuclear activities under the supervision of the International Atomic Energy Agency, a senior Iranian source told Reuters on Monday.

The source said ⁠that on the issue of Iran’s frozen assets, however, Washington has ⁠so far only agreed to free one-quarter of those assets according to a phased timetable. Iran wants the U.S. to reconsider both positions, the source said.

In its new proposal, the source said, Iran ⁠has again focused on securing ⁠an end to the war, ⁠reopening ⁠the Strait of Hormuz, and lifting maritime sanctions.

The more contentious issues around Iran’s nuclear program and uranium enrichment, which remain the most difficult parts of the negotiations, have been deferred to later rounds of talks.