The United States extended five of seven temporary waivers late last week to permit countries part of the 2015 Iran nuclear deal to conduct civil nuclear projects with the regime, but with limits as part of the Trump administration’s “maximum pressure” campaign against Tehran.

The waivers—extended to 90 days, down from the 180 days previously granted—allow the signees to continue conducting nonproliferation work at the Bushehr, Arak and Fordow nuclear facilities.

Simultaneously, the United States ended two waivers: one that permitted “the storage for Iran of heavy water it has produced in excess of current limits” in Oman, and another that allowed Iran to exchange enriched uranium for raw yellowcake with Russia.

“Iran must stop all proliferation-sensitive activities, including uranium enrichment, and we will not accept actions that support the continuation of such enrichment,” said U.S. State Department spokesperson Morgan Ortagus.

“Our policy preserves oversight of Iran’s civil nuclear program, reduces proliferation risks, constrains Iran’s ability to shorten its ‘breakout time’ to a nuclear weapon, and prevents the regime from reconstituting sites for proliferation-sensitive purposes,” she added. “We reserve the right to revoke or modify our policy covering these nonproliferation activities at any time if Iran violates its nuclear obligations or commitments or we conclude that such projects no longer provide value in constraining Iranian nuclear activities.”

Hook, the State Department special envoy on Iran, told CNN on Friday that the moves “enhance our ability to constrain Iran’s nuclear program while pursuing maximum economic pressure.”

America withdrew from the Iran deal last year and reimposed sanctions lifted under it, in addition to enacting new penalties against Tehran.

U.S. Sen. Ted Cruz (R-Texas) slammed Friday’s decisions.

“The @StateDept today took an important step by ending the notorious ‘Right To Enrich’ waiver that was part of the catastrophic Obama Iran nuclear deal, and which allowed Iran to swap enriched uranium for new supplies of uranium to feed into its nuclear program,” he tweeted in a thread. “Unfortunately, though, today’s decision was merely a half-measure. @realDonaldTrump rightly decided that maximum pressure means maximum pressure, but today the @StateDept instead once again extended critical parts of the Obama Iran deal.”

“Specifically, @StateDept granted waivers that allow the Ayatollahs to continue spinning centrifuges in the Fordow bunker that they dug into the side of a mountain to build nuclear weapons and also to continue working on their plutonium-producing Arak reactor,” Cruz subsequently tweeted. “For two and a half years, the career officials at State who drafted the Obama nuclear deal have fought tenaciously against President Trump’s resolve to end the deal. Enough is enough; when these nuclear waivers expire yet again in 90 days, they should end forever.”