Iran has stressed its nuclear activities are peaceful and in full compliance with the Non-Proliferation Treaty (NPT), after the UN nuclear watchdog said it has established a process to accelerate production of highly enriched uranium. 

"All nuclear programs and actions of the Islamic Republic of Iran are in full compliance with the NPT and Iran's commitments under the safeguards agreement, and have been carried out under IAEA supervision and with prior notice," said Saeed Khatibzadeh, spokesperson of Iranian Foreign Ministry.

In remarks published on the ministry's website, Khatibzadeh referred to the upgrading of Iran's nuclear activities as "compensatory measures" taken within the framework of the 2015 nuclear agreement, formally known as the Joint Comprehensive Plan of Action (JCPOA). 

The upgrading, he added, is a response to the "widespread violation" by the United States of the JCPOA and United Nations Security Council Resolution 2231, as well as the non-compliance of JCPOA parties. 

As long as the U.S. and other JCPOA parties do not implement the nuclear agreement "fully and unconditionally," the spokesman said, Iran will maintain its nuclear program on the sole basis of its own "needs and sovereign decisions" and within the framework of its NPT safeguards commitments. 

On Tuesday, details of an IAEA report to member states leaked to the press, showing Iran has increased the purity to which it is enriching uranium to 60 percent. 

Former U.S. President Donald Trump withdrew from the 2015 agreement in May 2018 and unilaterally re-imposed old and new sanctions on Iran. In response, Iran has gradually stopped implementing parts of its commitments to the deal since May 2019. 

After six rounds of talks in Vienna since April, the parties said serious differences remain between Iran and the U.S. for the revitalization of the deal. The sixth round of talks ended on June 20, with the talks currently on hiatus. 

(With input from Xinhua)