The Republican chairman of the Senate Foreign Relations Committee issued a rare challenge to the Trump administration Thursday: Prove to us that you are making progress with Russia over the war in Syria soon, or we will push forward with sanctions.

Sen. Bob Corker (R-Tenn.) has resisted efforts to debate and pass a bipartisan bill codifying existing executive sanctions against Russia for its aggressive actions in Syria and Ukraine and imposing additional sanctions over allegations of Russian meddling in the 2016 presidential election. Corker had argued that it was premature to consider such a measure before congressional investigators completed their probe into Russia’s activities.

On Thursday, Corker noted that Secretary of State Rex Tillerson had also asked him for “a short window of opportunity . . . to change the trajectory of our relationship with Russia” pertaining to Syria.

But Corker’s patience with Tillerson appears to be nearing its end.

“Unless Secretary Tillerson can come in early in this next work session” to tell senators that “these things are occurring that are changing the trajectory” of U.S.-Russian relations, Corker said he would recommend that the committee “quickly” move a bill to impose tougher sanctions on Moscow.

Corker did not specify how broad a spectrum of sanctions the committee should pursue, but he said that “likely one of the [bill’s] central themes would be Russian interference in our elections.” The Senate will be in recess for the week of Memorial Day and return to Washington in early June.

Corker expressed serious doubts that Tillerson could convincingly argue that anything in the relationship with Russia as it concerns Syria has improved as the Trump administration has promised. Corker noted that he recently reviewed classified documents on the state of affairs between Washington and Moscow, particularly concerning Syria.

“I can just tell you: I see no difference whatsoever,” Corker said. “They continue to work against our interests.”

Sen. Benjamin L. Cardin (D-Md.), the committee’s ranking Democrat, emphatically endorsed Corker’s plan, adding that he hoped the committee would advance the bill “early enough so that it could be considered on the [Senate] floor” during the next work period as well.

“I have no illusions that [Russian officials], in the next couple of weeks, are going to change their behavior,” Cardin said, noting that “I do look forward” to hearing from Tillerson.

The committee approved a bill to improve efforts to counter Russian propaganda and influence-peddling at home and abroad. The legislation was originally a subsection of a broader Russia sanctions bill that Cardin, Sen. John McCain (R-Ariz.) and a bipartisan group of senators introduced last month, but Cardin and Corker agreed to strip the sanctions provisions out, over the leaders’ dispute about whether Congress should attempt to advance Russia sanctions at all.

Corker’s move also prompted Sen. Jeanne Shaheen (D-N.H.), who was expected to try to force the issue of Russia sanctions back onto the Senate’s agenda by introducing amendments that would have revived the punitive measures in the Cardin-McCain bill, to hold back.

Shaheen’s amendments would have inserted such language back into the Russian propaganda bill and into a comprehensive bill stiffening sanctions against Iran for its recent ballistic missile tests and the activities of the Islamic Revolutionary Guard Corps, which the Trump administration is considering labeling as a terrorist organization.

The committee voted on both bills Thursday morning, approving the measure to improve Russian counter-propaganda efforts by a vote of 20 to 1, and the Iran sanctions bill by a vote of 18 to 3.

Though Shaheen withheld her amendments, she warned that “if we continue to fail to act,” it will only bolster Russia and other adversaries to “try to do the same thing to undermine our democracy.”

Corker responded sharply to Shaheen’s warning, reminding her that “I keep my word” and that he believed Tillerson would not be able to “demonstrably show that there had been a change.” He added that he had not been in touch with anyone in the White House about the matter, only Tillerson.

Corker also stressed that “a committee that prides itself on diplomacy” ought “to give the new secretary of state a few weeks to see if he can change the trajectory with Syria.”

“That’s what I agreed to do,” Corker said, adding: “I don’t think he will be able to.”

Committee leaders have yet to hammer out the details of what that Russia sanctions legislation will look like. Corker did not commit on Thursday to take up the exact language in the Cardin-McCain bill, despite bipartisan support for that measure.