Senate Democrats say the United States should keep economic sanctions in place until North Korea can verify that it has dismantled its nuclear and missile arsenal.

The Democrats are weighing in as President Donald Trump prepares to meet with North Korean leader Kim Jong Un next week in Singapore.

The Democrats say the president's goal must be the "full, complete and verifiable denuclearization of North Korea." They also say that the agreement must be a "permanent" one.

The senators are making their views known in a letter to the president. They are calling on the administration to fully inform Congress as negotiations proceed, including through classified briefings and full engagement with the Senate Foreign Relations Committee.

Senate Minority Leader Chuck Schumer, D-N.Y., and six other senators signed the letter.