Top US Senate leaders said on January 30 they are close to reaching bipartisan agreement on a sanctions bill that would “crush” Russia’s economy if it sends troops into Ukraine.

Senator Bob Menendez, the Democratic chairman of the Foreign Relations Committee, said it was crucial that the US send a clear message to Russian President Vladimir Putin that any such aggression is unacceptable.

“We cannot have a Munich moment again,” he said on CNN. “Putin will not stop with Ukraine.”

The legislation, he said, was near-complete: on the “one-yard line.”

Those stark comments came as Britain was completing its own sanctions package, one that Foreign Secretary Liz Truss said on January 30 would leave Russia with “nowhere to hide.”

Diplomatic efforts to resolve the crisis have continued, but fears are mounting amid an ongoing buildup that has placed more than 100,000 Russian troops on Ukraine’s borders.

Menendez appeared together with the ranking Republican on the Foreign Relations committee, Senator James Risch, in an apparent show of bipartisan determination.

Risch said a bipartisan coalition of senators had been making a “24-hour-a-day” effort to complete a sanctions bill that could persuade Putin that an invasion would carry extraordinarily high costs.

“It’s going to be extremely painful,” Risch said.

“This is not the same as Crimea,” when Russian troops invaded and annexed Ukraine’s Crimea peninsula in 2014, he added. “There is substantially, substantially more worldwide opposition.”

He warned that no one should take the sanctions threat lightly, saying that because of Russia’s heavy involvement in the energy sector, an invasion of Ukraine would ultimately “have a devastating effect on the economy around the world when it comes to the price of gasoline.”

Despite the show of comity between Menendez and Risch, there has been debate on the timing of a sanctions package, with some Republicans saying it should take force now, while some Democrats want to hold the threat in abeyance.

“There are some sanctions that really could take place up front because of what Russia has already done: cyber attacks on Ukraine, false flag operations, the efforts to undermine the Ukrainian government internally,” Menendez said.

But, he added, “the devastating sanctions that ultimately would crush Russia would come later on when he invades.”

As talks aimed at defusing the crisis continued in several capitals, the US ambassador to the UN emphasised on January 30 that a diplomatic solution is still possible.

In talks with all parties, said Ambassador Linda Thomas-Greenfield, “we have made clear that we’re prepared to address our concerns, Ukrainian concerns and Russian concerns at the diplomatic table. But it cannot be done on the battlefield.”

She was echoing a message sent two days earlier by US Defence Secretary Lloyd Austin.

“Conflict is not inevitable,” he said. “There is still time and space for diplomacy. Mr Putin can do the right thing.”