MOSCOW — A Russian lawyer in the forefront of recent street protests in Moscow was arrested Monday evening in the Russian capital, along with a second opposition activist and an elected local councilor in what appeared to be a sweep by the authorities of protest leaders not already in detention.

The arrests in Moscow targeted Lyubov Sobol, a 31-year-old lawyer who works for Russia’s Anti-Corruption Foundation, an independent group led by Aleksei A. Navalny, another anti-corruption campaigner; Nikolai Lyaskin; and Ilya Azar, a journalist with Novaya Gazeta, an independent daily newspaper, and a local councilor.

Ms. Sobol, the most prominent of the activists known to have been picked up on Monday, has been one of the main public faces of a recent wave of protests, including a peaceful march attended by several thousand people that she led on Saturday through the center of Moscow.

Released from provisional arrest after midnight pending a court hearing, Ms. Sobol said on her Twitter account after her release that she had been picked up by police officers as she was leaving a store and accused of taking part in an illegal gathering.