Sen. Charles Schumer (D-NY), in a letter to the White House, commended the administration on its effort to impose crippling sanctions on Iran and warned it not to ease them before Iran completely dismantles its nuclear weapons program.

Schumer cautioned the administration about dealing with the Iranian regime at forthcoming negotiations, set to resume in Moscow later this month, and pointed to the regime’s “long track record of delay, lies and deception.”

The senator laid out three conditions for the U.S. and partners during the negotiations: Iran must shut down its nuclear enrichment plant at Fordo; Iran must stop all enrichment of uranium; and Iran must transfer the uranium it has enriched to 20 percent out of the country to a trusted partner country.

“The cost of inaction is simply too great; preventing a nuclear Iran must remain our highest priority,” Schumer wrote.