United States officials declined, without explanation, to provide the text of the resolution.

The proposed measures, according to a United States official, would ban the trade of conventional weapons, luxury goods like jet skis and Rolex watches, and aviation fuel to North Korea, which could effectively ground its national airline. It would also place prohibitions on dozens of new companies and individuals accused of trafficking in illicit nuclear material.

In what may be the toughest proposed measure, all North Korean cargo entering or leaving a country must be inspected by that country.

The mandatory cargo inspection applies to “anything going to and from the D.P.R.K.,” according to an American official who spoke on the condition of anonymity because of the delicacy of the talks. “If it is on your territory, in your ports or in your airports, there’s a requirement to inspect cargo to and from the D.P.R.K.,” the official said, using the initials for the Democratic People’s Republic of Korea.

In addition, 31 ships that have been known to traffic in illegal nuclear goods are to be banned from docking in any port. It is impossible to verify whether countries sending or receiving North Korean goods will carry out the inspections. However, they will be legally binding if the resolution is adopted.

Significant loopholes remain. North Korea would still be able to buy oil and sell its coal and iron ore, as long as it is not being used to fund its nuclear weapons program — which would be difficult to prove. China, North Korea’s main trading partner and diplomatic backer, is its main supplier of oil.