The United States is pushing for a vote as early as Monday on new sanctions that would impose an energy stranglehold on North Korea by banning sales of oil and natural gas to the reclusive country.
Negotiations were expected to take place this weekend, with China and Russia expressing objections.
According to a draft version of a U.S.-written United Nations resolution, Pyongyang would be prohibited from importing "crude oil, condensate, refined petroleum product and natural gas liquids."
The draft resolution, which is being circulated at the U.N. Security Council, would also ban Pyongyang from exporting textiles — nipping in the bud one of the fastest growing sectors of the North Korean economy. And it would increase the ability of U.N. member states to interdict ships on the high seas by allowing "nonconsensual inspections" of those designated as violating sanctions.
If approved and enforced, the bans would be crippling for North Korea, as the Trump administration and other governments seek ways to curb the isolated nation's robust nuclear program.
"It's not a complete quarantine, but it is getting close," said Scott Snyder of the Council on Foreign Relations.
But already the draft has run into opposition from China, which is North Korea's chief trading partner and largest supplier of fuel, and from Russia. China's ambassador to the U.N., Liu Jieyi, reportedly cut short a trip to Africa to negotiate over the weekend on the resolution.
Russian President Vladimir Putin, speaking at an economic forum with several Asian leaders in eastern Russia, expressed some sympathy for North Korean President Kim Jong Un's desire to have nuclear weapons but also said he was confident "common sense" would prevail.
"We can solve this problem through diplomatic means," Putin said Thursday.
Chinese Foreign Minister Wang Yi said his country agreed on the need for additional Security Council action but at the same time urged "dialogue and consultation."
Secretary of State Rex Tillerson has spent the last several days on the telephone trying to muster support for the U.S.-proposed resolution, his spokeswoman, Heather Nauert, said Thursday.
Nauert insisted that North Korea's nuclear test last weekend, its most powerful to date, did not show that diplomacy was failing.
Numerous countries "are all coming together to condemn" North Korea, she said. Changing Kim's behavior "will take time."
The draft resolution also bars U.N. countries from employing North Korean guest workers, who typically send almost all their earnings home to support the Pyongyang government, strengthening a clause of last month's unanimously approved U.N. resolution that merely capped the number of North Korean workers abroad.
"China and Russia will likely object to these measures and insist on loopholes reducing their effectiveness," said Anthony Ruggiero, a senior fellow for the Foundation for Defense of Democracies and an expert in sanctions.
North Korea is entirely dependent on imported fuel oil, most of it from China. In the past, Beijing has cut off Pyongyang's supply, but only briefly, in order to signal displeasure.
North Korea has already made its thoughts known:
"We will respond to the barbaric plotting around sanctions and pressure by the United States with powerful countermeasures of our own,'' the North Koreans said in a statement Thursday attributed to an economic delegation attending the economic forum in Vladivostok, Russia.
North Korean defectors have reported rising gas prices, leading to speculation that China has already reduced its sales to North Korea or, alternately, that the North Korean military has been stockpiling fuel in anticipation of new sanctions.
Demick reported from New York and Wilkinson from Washington