WASHINGTON — U.S. sanctions against Russia over the poisoning of a former spy and his daughter in the United Kingdom go into effect Monday.

The Trump administration announced earlier this month its intention to impose the sanctions after the U.S. determined that Russia had illegally used a chemical weapon in the poisoning of Sergei and Yulia Skripal.

Details of the measures were published in the Federal Register on Monday. The sanctions tighten restrictions on exports of national security-sensitive items but provide waivers in areas such as commercial passenger aviation.

A second set of sanctions is required in three months unless Russia provides assurances it won't use chemical weapons again. Those sanctions could hit Moscow harder if they target Russia's state-controlled banks.

Moscow denies it poisoned the Skripals.