You are not permitted to download, save or email this image. Visit image gallery to purchase the image.
The leftist was among several opposition figures charged with riots and violence against police during a protest against President Vladimir Putin last May on the eve of his inauguration for a third presidential term.
The Federal Investigative Committee, which answers only to Putin, had barred Udaltsov from travelling freely but said on Friday that he was not complying with that.
The court put Udaltsov under house arrest until April 6.
The shaven-headed Udaltsov has been repeatedly detained during opposition protests, in what his supporters say is a tactic intended to hamper his activism.
On Thursday, another opposition activist was arrested over the May protests. That brought to 12 the total number of people detained and awaiting trial. One person has already been convicted over the May unrest.
Meanwhile, Russian police have detained 271 people, most of them from the North Caucasus and central Asia, in an investigation into involvement in "terrorist activities", authorities in St Petersburg said.
Russia is concerned that Islamist militants could become a greater threat outside the heavily Muslim North Caucasus region, plagued by an insurgency rooted in two post-Soviet separatist wars in the republic of Chechnya.
In a statement, the regional investigative committee in St Petersburg said that most detainees were from the North Caucasus and the former Soviet republics of Uzbekistan, Tajikistan and Azerbaijan. An Egyptian and an Afghan were also detained.
The committee said they were detained "in order to check if they had legal grounds for being in St Petersburg and their possible involvement in terrorist activities."
They were detained during an overnight raid on St Petersburg's oldest market.
Authorities said security forces had been searching for extremist literature, weapons, drugs and documents related to a recently-launched criminal case in connection with "public justification of terrorism and incitement of hatred".
The authorities did not say whether any of those detained were suspected of involvement in plotting or carrying out attacks.
Many market traders in Russian cities are from the North Caucasus or central Asia.
Local media said police had initially detained 700 people.