Vladimir Kara-Murza Jr., a prominent Russian opposition figure and critic of the Kremlin's war in Ukraine, was detained in the capital Moscow late Monday.

Ilya Yashin, another leading opposition figure, said on Twitter that Kara-Murza was detained Monday near his Moscow residence.

Kara-Murza, 40, was set to stay in police custody overnight, his lawyer, Vadim Prokhorov, said. He was charged with failing to follow a lawful order of a police officer, a military service member, an officer of the federal security services.

The charge carries a penalty of up to 15 days in prison. Nothing was initially known about other allegations.

Kara-Murza was hospitalized with poisoning symptoms twice, in 2015 and 2017. A journalist and associate of Russian opposition leader Boris Nemtsov, who was shot and killed in 2015, and oligarch-turned-dissident Mikhail Khodorkovsky, Kara-Murza nearly died from kidney failure in the first incident. He suspects he was poisoned but no cause has been determined.

Kara-Murza was taken to a hospital with a sudden, similar illness in 2017 and put into a medically induced coma. His wife said doctors confirmed that he was poisoned.

According to research by the investigative group Bellingcat, Kara-Murza was being pursued by agents of the Russian domestic secret service FSB, who are said to be involved in the poisoning of Russian dissident Alexei Navalny.

"The United States is troubled by Russian authorities' detention today in Moscow of prominent civil society leader Vladimir Kara-Murza," U.S. Secretary of State Antony Blinken said in a tweet.

"We are monitoring this situation closely and urge his immediate release."