During the phone talk on Saturday night, Zarif underscored Iran's serious political resolve and will to settle the country's nuclear standoff with the West.
He also said that if the G5+1 (the five permanent UN Security Council members plus Germany) shows serious political will to recognize Iran's inalienable nuclear rights, Tehran's nuclear issue will be resolved.
Ashton, for her part, expressed the hope that the negotiations between Iran and the world powers would resume as soon as possible.
On April 6, Iran and the six world powers wrapped up their 4th round of talks after two days of intensive negotiations in Almaty, Kazakhstan.
The Iranian team was led by Iran's top negotiator Saeed Jalili, who is also the Secretary of Iran's Supreme National Security Council (SNSC), and the G5+1's representatives were presided by Ashton.
Iran had announced a day prior to the start of the talks that it would enter the negotiations with the G5+1 with clear, groundbreaking proposals.
Iran has so far ruled out halting or limiting its nuclear work in exchange for trade and other incentives, saying that renouncing its rights under the Non-Proliferation Treaty (NPT) would encourage the world powers to put further pressure on the country and would not lead to a change in the west's hardline stance on Tehran.
Iran is under four rounds of UN Security Council sanctions for turning down West's calls to give up its right of uranium enrichment. The United States and the European Union have ratcheted up their sanctions on Iran this year to force it to curb its nuclear program.
Iranian officials have always shrugged off the sanctions, saying that pressures make them strong and reinvigorate their resolve to further move towards self-sufficiency