"I think the idea here is we are watching those nuclear activities very, very closely," Bolton said in an interview with Fox Business. "So this is a short, 90-day extension."
Earlier in the day, an unnamed source with told the Washington Post that "these [sanctions] waivers can be revoked at any time, as developments with Iran warrant. But because of the Treasury Department’s legitimate concerns, we’ve decided to extend them for now.”
This will be the second time the US has extended sanctions waivers to only the Arak, Fordow and Bushehr power plants and facilities in the Islamic Republic.
The extension allows Russia, China and European nations to continue projects with the Iran-based facilities without incurring US sanctions.
The related countries' civilian nuclear cooperation projects were established under the guidelines laid out in the 2015 Joint Comprehensive Plan of Action (JCPOA), also known as the Iran nuclear deal, which crumbled following US President Donald Trump's choice to withdraw Washington from it on May 8, 2018.
On Tuesday, Washington issued a formal request to London, Paris and Berlin to join in combating alleged aggression from Tehran in the Hormuz Strait.
Germany and France have expressed hesitation regarding the US' "maximum pressure" campaign, and German Foreign Minister Heiko Maas issued a statement calling for a diplomatic, non-military solution.
"We must make every effort to avoid a further escalation in the Strait of Hormuz … We will look for a way to ease tensions. There can be no military solution to it," Maas said.