Congress is moving toward slapping stricter sanctions on North Korea as diplomatic efforts flounder.

The sanctions, which aim to plug what Sen. Chris Van Hollen Christopher (Chris) Van HollenCongress must finish work on popular conservation bill before time runs out Democrats fear Russia interference could spoil bid to retake Senate Mid-Atlantic states sue EPA over Chesapeake Bay pollution MORE (D-Md.) described as a “leaking” sanctions regime, were added as an amendment to the annual defense policy bill that passed the Senate on Thursday.

The House version of the National Defense Authorization Act does not contain the sanctions, but sponsors of the provision are confident it will survive bicameral negotiations based on conversations with House members.

ADVERTISEMENT

“We’ve seen two summits — we had the Singapore summit and the Hanoi summit — and we held off on pushing the legislation during those negotiations, but now that they’ve fallen apart, we thought it was important to take this next step,” Van Hollen said Thursday about President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE's two meetings with North Korean leader Kim Jong Un Kim Jong UnPelosi knocks Trump over refusal to commit to peaceful transfer of power Satellite images indicate North Korea preparing for massive military parade South Korea warns of underwater missile test launch by North Korea MORE.

Van Hollen was speaking at a news conference touting the sanctions alongside fellow co-sponsors Sens. Pat Toomey Patrick (Pat) Joseph ToomeyAppeals court rules NSA's bulk phone data collection illegal Dunford withdraws from consideration to chair coronavirus oversight panel GOP senators push for quick, partial reopening of economy MORE (R-Pa.), Sherrod Brown Sherrod Campbell BrownMnuchin says he and Pelosi have agreed to restart coronavirus stimulus talks Harris faces pivotal moment with Supreme Court battle Remote work poses state tax challenges MORE (D-Ohio) and Rob Portman Robert (Rob) Jones PortmanMcConnell locks down key GOP votes in Supreme Court fight Romney undecided on authorizing subpoenas for GOP Obama-era probes Congress needs to prioritize government digital service delivery MORE (R-Ohio).

The bill is called the Otto Warmbier Banking Restrictions Involving North Korea Act, after the student who died after being returned from North Korean detention in a coma. Its sanctions are modeled after ones against Iran in 2010 and 2012 credited with bringing Tehran to the negotiating table.

Supporters say the bill, which would impose secondary sanctions on financial entities doing business with North Korea, is necessary to target those helping Pyongyang evade existing sanctions. The secondary sanctions are expected to particularly hit Chinese banks.

“They would present Chinese banks with a very simple choice: You can do business with the United States or you can do business with North Korea, but you can’t do both,” Toomey said.

Trump’s Hanoi summit with Kim in February ended without a deal after differences in what the United States and North Korea were willing to give on sanctions relief and denuclearization, respectively.

In the following months, talks appeared to be at a standstill, and North Korea tested several short-range missiles. But more recently, Trump and Kim have started to exchange flattering letters again, with Trump saying this week that Kim recently sent him a birthday greeting.

Trump is scheduled to visit South Korea following his current trip to Japan for the Group of 20 summit. The White House has said there are no plans for Trump and Kim to meet while Trump is on the Korean Peninsula.

In March, Trump also said he did not think new North Korea sanctions were necessary, saying he wanted to maintain a good relationship with Kim.

On Thursday, Toomey insisted the Trump administration is behind Congress’s latest effort at North Korea sanctions.

“I’m not aware of any resistance from the administration,” he said. “As I said, this is no surprise to the administration. We’ve worked with administration officials, and I think they welcome tightening the screws on North Korea. They recognize the need for that.”