U.S President Donald Trump has signed the Russia sanctions bill Congress forced on him, and is adding a statement saying the administration will carry out the law but with reservations about its impact and the constitutionality of some provisions.

The signing statement lays out the President’s concerns about the legislation, including that it encroaches on presidential authority and may hurt U.S. ability to work with allies.

Trump’s statement doesn’t signal any intent to bypass or circumvent aspects of the law. Instead, the president indicates he intends for his administration to carry out the law in a way consistent with his constitutional authority, language that leaves open some room for interpretation of how the law is executed.

Trump’s concerns cover four areas: encroachment on executive authority, unintentional harm to U.S. companies and business, as well as U.S. international partners, and limits on the flexibility of the administration to act in concert with allies in dealing with Russia.

The European Union has warned of possible retaliation if European companies are hobbled by sanctions aimed at squeezing Russia’s energy exports.

The legislation, passed by overwhelming margins in the U.S. House and Senate, strengthens sanctions on Russia and gives Congress the power to block the president from lifting them. The bill also imposes new sanctions on Iran and North Korea.

The Russia sanctions and the restrictions placed on Trump marked a rare rebuke for the president from congressional Republicans. Lawmakers decided to limit the president’s ability to ease penalties on Russia at a time when House and Senate committees and the Federal Bureau of Investigation are examining whether some members of his political campaign may have colluded with Russian interference in the 2016 election.

Passage of the legislation sparked retaliation by the Russian government, which ordered the U.S. to slash hundreds of embassy and other personnel in the country. The events have raised tension between the two nuclear-armed nations, putting the relationship at its lowest point since the Cold War.

Lawmakers said they wanted to prevent the president from acting unilaterally to lift penalties imposed by Trump’s predecessor, former President Barack Obama, for meddling in last year’s U.S. election and for aggression in Ukraine.

White House officials had argued that it hampered the president’s ability to negotiate. But the legislation cleared both the House and Senate by wide margins, indicating any presidential veto would be overridden. Recent presidents including Obama and George W. Bush also used signing statements to express displeasure or signal planned modifications to legislation they felt compelled to sign over their own objections.

“This is an area, though, where the administration is going to be watched very carefully,” said Peter Feaver, a Duke University professor and director of the Triangle Institute for Security Studies, who served on the National Security Council staffs of Presidents Bill Clinton and George W. Bush. This sanctions bill, he said, was passed “by overwhelming majorities in both houses and it’s on one of the most important issues of the day. If the president tries to wiggle out from under the constraints of the law, I think he will pay a high political price for doing so.”

Feaver also said he expects Congress will replace this sanctions bill with one that returns more flexibility to Trump once the administration comes up with a clear and tough Russia policy.