A bipartisan duo in the Senate has introduced legislation that would require the Trump administration to impose tougher sanctions on North Korea and provide Congress with a strategy for curbing that country’s nuclear and missile programs.

“The administration has taken positive steps in recent weeks to impose additional sanctions and working with governments to diplomatically isolate this heinous regime.” Sen. Cory Gardner (R-Colo.) said in a statement Tuesday.

“Sen. [Ed] Markey and I are going to continue working in a bipartisan manner to give nations and companies a clear choice — do business with the United States or do business with North Korea.”

Gardner and Markey (D-Mass.) are the chairman and ranking member, respectively, of the Senate Foreign Relation’s subcommittee on East Asia, the Pacific and international cybersecurity.

Their bill, dubbed the Leverage to Enhance Effective Diplomacy Act of 2017, comes at a time when President Trump has muddied the waters on his diplomatic strategy by calling out Secretary of State Rex Tillerson.

On Saturday, Tillerson acknowledged that the United States has been in direct contact with North Korea. A day later, Trump tweeted that Tillerson was “wasting his time.”

“I told Rex Tillerson, our wonderful Secretary of State, that he is wasting his time trying to negotiate with Little Rocket Man,” Trump tweeted, using his nickname for North Korean leader Kim Jong Un.

“Save your energy Rex, we’ll do what has to be done!” Trump continued.

The White House on Monday sought to clarify, saying Trump still has faith in Tillerson and that the only talks have been about Americans detained in North Korea.

The row comes after the Trump administration imposed its toughest sanctions yet on North Korea, targeting banks around the world that do business with the country.

On Tuesday, Markey said economic pressure has to be coupled with talks to convince Kim the United States is not a threat.

“There is no military solution to the threat of a nuclear North Korea,” Markey said in a statement. “While the effort to economically and politically isolate North Korea will be essential for a diplomatic strategy to succeed, we must also recognize that pressure, without diplomatic engagement, will quickly become counterproductive.”

Under Gardner and Markey’s bill, the president would be required to block all transactions that are property of the North Korean government, affiliates or those that conduct significant business activities with North Korea.

The bill would also require the president to block any entity or financial institution implicated in any significant trade in goods or services with North Korea from the U.S. financial system, including the top 10 companies doing business with North Korea.

In addition to sanctions, the bill would require the president to produce strategies on addressing the nuclear and ballistic missile threat posed by North Korea, ending North Korean labor trafficking practices around the world and globally isolating North Korea diplomatically and economically.

To isolate Pyongyang, the secretary of State would need to give Congress a list of countries considered non-cooperative in those efforts, and the administration would be authorized to downgrade relations or reduce aid to those countries.

The bill would also require the administration to brief Congress no more than 30 days after U.S. official diplomatic engagement with North Korea, provide a report on detained U.S. citizens and provide a report on the use and strategy to end the procurement of certain rocket fuels.

Finally, the bill would reauthorize for five years the North Korea Human Rights Act of 2004, which provides for humanitarian aid and disseminating information to North Koreans.