(Reuters) - U.S. lawmakers said on Monday they did not know when legislation to impose new sanctions on Russia might come up for a vote in the House of Representatives, and the White House said it had concerns about the measure.

The legislation passed the Senate by a nearly unanimous margin two weeks ago, looking like it might complicate President Donald Trump's desire for warmer relations with Moscow, where officials have denounced new sanctions.

Republican Senator Bob Corker, chairman of the Senate Foreign Relations Committee and a co-author of the legislation, said he hoped for progress within the next day or two on a procedural issue that has kept the House from taking up the Countering Iran's Destabilizing Activities Act, which also includes the new sanctions against Russia.

A White House official said the Trump administration felt some provisions in the bill would interfere with its ability to use sanctions to try to influence Russia.

"There are some provisions in the Senate bill that would unprecedentedly impair Treasury's ability to wield its sanctions tools, risk endangering the transatlantic sanctions coalition, and weaken the State Department's ability to credibly signal that we would calibrate our sanctions in response to Russian behavior," the official said in an emailed statement, requesting anonymity.

The measure must pass the House, where Trump's fellow Republicans control a larger majority than in the Senate, before it can be sent for Trump to sign into law or veto.

House Republican leaders said last week that the Senate bill violated a constitutional requirement that any bill affecting government revenues must originate in the House, something known as a "blue slip" violation.

House aides also said leadership had not yet decided whether to vote on the Senate bill once the "blue slip" issue was resolved, or first refer it to House committees, which could further delay or change it.

Democrats said they were skeptical about the "blue slip" explanation, noting that the issue had resolved very quickly in recent years for other bills.

Corker said Senate Republicans remained solidly behind the legislation. "I've heard no one here have second thoughts, by the way" he told Reuters. "If you find one, please tell me."

White House spokesman Sean Spicer declined comment during a news briefing on Monday on whether the administration would support the sanctions bill.