The Trump administration has hailed the latest United Nations sanctions against nuclear-armed North Korea as the most severe yet, and the North’s fury over the penalties suggested they carried some sting.

In a staccato of outraged reactions on Monday to the sanctions imposed over the weekend, North Korea threatened retaliation against the United States “thousands of times” over, vowed to never give up its nuclear arsenal and called the penalties a panicky response by an American bully.

But it is unclear at best, experts on sanctions say, whether the measures will hinder North Korea’s nuclear militarization or even crimp its economy.

The sanctions are aimed at pressuring North Korea into negotiating, with the goal of renouncing its nuclear weapons. But Kim Jong-un, the North’s leader, has repeatedly said that the country’s nuclear capabilities are crucial to its self-defense.