A bipartisan group of senators is warning the Trump administration against returning U.S.-based diplomatic compounds to Russia that were seized in response to Moscow’s election meddling.

The letter followed a Washington Post report last week that the administration is considering returning the diplomatic properties — one on Long Island and another on Maryland’s Eastern Shore — to Russia.

“Returning the compounds to Russian control is unjustifiable,” the senators, including Republican Lindsey Graham (S.C.), wrote to President Trump on Wednesday.

“It would both make it easier for the Kremlin to continue its intelligence operations in our own backyard and make it clear that they can avoid consequences for their actions. We strongly advise against it,” they added.

The letter was also signed by Sens. Amy Klobouchar (D-Minn.), Kirsten Gillibrand (D-N.Y.) and Chris Van Hollen (D-Md.).  

In late December, then-President Barack Obama shuttered the compounds on the grounds that they were being used for “intelligence-related purposes.”

The decision, along with the expulsion of several Russian diplomats from the U.S. and new sanctions on Moscow, was in response to Russian interference in the presidential election — which Russia has denied.

“These properties were seized because 17 U.S. intelligence agencies confirmed that Russia used covert cyberattacks, espionage, and harmful propaganda to try and undermine our democracy, in addition to the fact that U.S. diplomats in Russia faced repeated harassment from Russian security services,” the senators wrote.

“We need to stand strong and stand united so that Russia and other nations know that this aggression will not go unchecked,” they added.

The return of the compounds was initially explored as a potential exchange for the Russians lifting a hold on construction of a U.S. consulate in St. Petersburg, according to the Post.

In response to the report, a senior communications adviser for the State Department told NBC, “The U.S. and Russia have reached no agreements. The next meeting will be in June in St. Petersburg.”

A State Department aide offered no details of the timing of the meeting when contacted by The Hill.

Secretary of State Rex Tillerson has said that Russian election interference is “fairly well-established” and has noted the low point in U.S.-Russia relations over the conflict in Syria.

Still, Wednesday’s letter points to fears in Washington about the prospect of the Trump administration easing penalties on Russia levied in response to the election interference.

The FBI is currently probing any links or coordination between Trump campaign associates and Moscow, as part of its broader investigation into Russia’s actions.