The United States says it is eyeing fresh sanctions against Russia over the poisoning of a Russian former spy in Britain earlier this year.
The State Department announced on November 6 that it will consult with Congress on the fresh sanctions after Russia failed to meet a three-month deadline to comply with a 1991 U.S. law on preventing the use of chemical weapons.
The United States and its allies accuse the Russian government of involvement in the March nerve agent attack on Sergei Skripal and his daughter, Yulia, in the English city of Salisbury.
Moscow strongly denies it was behind the poisoning, which has added tension to already severely strained ties between Russia and the West, leading to additional U.S. and European Union sanctions on Moscow and to diplomatic expulsions of Russian and Western officials.
The State Department determined in August that Russia violated the 1991 Chemical and Biological Weapons (CBW) Act in the Skripal case, and imposed a first round of sanctions targeting foreign aid, the sale of defense and security goods, and U.S. government loans for exports to Russia.
Under the law, Washington must impose a second round of penalties unless Russia is found to have taken action to prove its compliance with the U.S. law within 90 days.
"We intend to proceed in accordance with the terms of the CBW Act, which directs the implementation of additional sanctions," State Department spokeswoman Heather Nauert said in a statement as the deadline fell on November 6.
In September, Britain charged two Russian citizens -- identified as military intelligence officers Anatoly Chepiga and Aleksandr Mishkin -- with trying to kill the Skripals.
British authorities allege that the two Russians smeared a Soviet-designed nerve agent called Novichok on the front door of Skripal's home in Salisbury on March 4, the day the former Russian intelligence officer and his daughter were found incapacitated on a bench and rushed to the hospital.
Both survived after weeks in critical condition, but Dawn Sturgess, a woman who authorities said came in contact with the poison after her boyfriend found a fake perfume bottle containing it, died in July.
Skripal, a former colonel in the Russian military intelligence agency known as GRU, was convicted of treason in 2006 by a Russian court and had been serving a 10-year prison sentence when the swap, in which 10 sleeper agents including Anna Chapman were sent home to Russia from the United States, took place.