Russian opposition figure Vladimir Kara-Mursa was arrested by police outside his home in Moscow on Monday.
Kara-Mursa had to stay overnight in a police station, his lawyer Vadim Prokhorov said.
He was charged with resisting state authority.
According to Russian law, this can result in a prison sentence of up to 15 days.
Nothing was initially known about other allegations.
However, Kara-Mursa is a prominent critic of President Vladimir Putin.
The 40-year-old politician and journalist has twice narrowly survived mysterious poisonings for which he blames the Russian secret service.
According to research by the investigative group Bellingcat, Kara-Mursa was being pursued by agents of the Russian domestic secret service FSB, who are said to be involved in the poisoning of opposition leader Alexei Navalny.
US Secretary of State Anthony Blinken expressed concern about Kara-Mursa's arrest.
"We are closely monitoring the situation and demand his immediate release," he wrote on Twitter.