Some of President Obama’s closest Democratic allies are joining Republicans in calling on the administration to reverse course and sanction Iran for illicit missile tests.

The White House had notified Congress of looming sanctions last week and then abruptly pulled back, without offering a specific explanation for the delay.

Republicans swiftly slammed the decision as a weak-kneed response to an increasingly belligerent regime, but top Democrats including party Chairwoman Debbie Wasserman Schultz are now joining in -- urging the administration to act “immediately” to penalize Tehran.

“The United States and our allies must take immediate, punitive action and send a clear message to Iran that violating international laws, treaties, and agreements will have serious consequences,” Schultz, D-Fla., and six other House Democrats wrote in a letter Wednesday to Obama.

They urged the administration to act on the sanctions “without further delay” and issued a stark warning about the risk of holding back in light of the nuclear deal.

“Inaction from the United States would send the misguided message that, in the wake of the [nuclear deal], the international community has lost the willingness to hold the Iranian regime accountable for its support for terrorism and other offensive actions throughout the region,” they wrote.

The lawmakers pointed to several Iranian missile launches – including a test in October deemed a violation of a U.N. Security Council resolution, and another in November that the U.N. has not yet ruled on. They also cited reports last week that an Iranian rocket came within 1,500 feet of a U.S. aircraft carrier in the Strait of Hormuz.

“Such aggressive and destabilizing behavior is deeply troubling, particularly preceding implementation of the Joint Comprehensive Plan of Action (JCPOA), and demands a U.S. response,” they wrote.

In the wake of those aggressions, the administration last week had notified Congress of plans to impose financial penalties on companies and individuals tied to Iran’s missile program. But then the administration held back, reportedly citing “evolving diplomatic work.”

Ben Rhodes, a deputy national security adviser, said “additional work” needs to be done before any announcement and stressed that the Iranians do not “get a say” in the decision. Rhodes also said the “additional work” is not based on push-back from Iran.

On Monday, White House Press Secretary Josh Earnest insisted sanctions would be imposed.

“Ultimately, we will impose those financial penalties -- we’ll impose those sanctions at a time and place of our choosing when our experts believe they would have the maximum impact,” he said. “And those decisions are not subject to negotiation by the Iranians -- or anybody else for that matter.”

Earnest also was asked about reports that Saudi Arabia – which cut ties with Iran earlier this week amid an escalating diplomatic crisis – may have been irritated over Washington’s lack of punitive action against Iran.

“You’d have to ask them about that,” Earnest said.

Hawkish Republican lawmakers have also pressed the administration to act.

“The Obama administration should impose a strong set of sanctions on Iran for its tests of ballistic missiles capable of delivering nuclear weapons,” Sens. Mark Kirk, R-Ill.; Kelly Ayotte, R-N.H.; Richard Burr, R-N.C.; and Lindsey Graham, R-S.C., said in a statement this week.

They said the administration should not provide sanctions relief under the nuclear deal until the country “verifiably ends all military dimensions of its nuclear program, including the development of ballistic missiles capable of carrying a nuclear weapon.”

The Associated Press contributed to this report.