Iran announced the beginning of 60% uranium enrichment on Tuesday. Such a level, which is nearing the degree required to develop a nuclear weapon, violates the Iran nuclear agreement at a time when the United States is seeking to return to it.

On Tuesday, Iranian Deputy Foreign Minister for Political Affairs Abbas Araghchi informed the International Atomic Energy Association, which regulates the international use of nuclear energy, that Iran would begin enriching uranium at 60%. The increase was in response to the alleged Israeli cyberattack on the Iranian nuclear facility in Natanz on Sunday, the state Mehr News Agency reported.

Uranium enrichment is the process by which certain parts of the chemical element uranium are isolated. The process is necessary to develop nuclear energy, and a nuclear weapon can be built when uranium levels reach 90%.

The 2015 Joint Comprehensive Plan of Action (JCPOA), more commonly known as the Iran nuclear deal, required Iran’s enrichment levels to not exceed 3.67%. The agreement sought to remove the threat of a nuclear Iran in exchange for removing sanctions on the Islamic Republic.