U.S. allies in Europe are signaling a willingness to enter into talks with the Trump administration alleviate worries about the Iran nuclear agreement, even as they insisted support for the 2015 deal aimed at putting Iran's nuclear program in check.

"We share concerns about Iran's ballistic missile program and regional activities that also affect our European security interests," British Prime Minister Theresa May, French President Emmanuel Macron, and German Chancellor Angela Merkel said in a joint statement. "We stand ready to take further appropriate measures to address these issues in close cooperation with the U.S. and all relevant partners. We look to Iran to engage in constructive dialogue to stop de-stabilizing actions and work towards negotiated solutions."

Trump declined to certify that the nuclear deal is vital to national security interests, but he stopped short of imposing the sanctions that former President Barack Obama waived as part of the agreement. The application of sanctions would amount to an abrogation of the pact, but Trump's congressional allies hope the threat of sanctions will convince Iran to come back to the negotiating table.

"In the event we are not able to reach a solution working with Congress and our allies, then the agreement will be terminated," Trump said. "It is under continuous review and our participation can be cancelled by me at any time."

While Trump's European counterparts indicated a willingness to talk further, they urged Trump not to abandon the deal altogether. "We encourage the U.S. Administration and Congress to consider the implications to the security of the U.S. and its allies before taking any steps that might undermine the JCPOA, such as re-imposing sanctions on Iran lifted under the agreement," they said. "We have asked our Foreign Ministers to consider with the U.S. how to take these issues forward."

The three European leaders said they "stand committed" to the Iran nuclear agreement, despite President Trump's refusal to certify that it supports American national security interests.

"The nuclear deal was the culmination of 13 years of diplomacy and was a major step towards ensuring that Iran's nuclear program is not diverted for military purposes," they said. They also emphasized that international monitors have "repeatedly confirmed Iran's compliance" with the deal.