MOSCOW -- Police have reportedly detained six activists at an improvised memorial near the Kremlin where Russian opposition politician Boris Nemtsov was gunned down two years ago.
The website OVD-Info, which tracks arrests in Russia, said police detained six people on the Bolshoi Moskvoretsky Bridge late on February 26. City workers who came to the bridge with police removed flowers and candles that had been placed at the site.
The actions by the authorities came after about 15,000 people marched in central Moscow to honor the memory of Nemstov -- the largest opposition gathering in Russia since a similar march in 2016.
Nemtsov, a vocal critic of President Vladimir Putin, was fatally shot on the bridge on February 27, 2015.
Five suspects from Russia's North Caucasus region are being tried for Nemtsov's killing, but relatives and supporters believe those who carried out the contract-style killing were following orders from someone higher up.
They say justice will not be done until those behind Nemtsov's killing are identified, tried, and convicted.
U.S. Ambassador John Tefft visited the makeshift memorial on February 27, and the United States urged the Russian government to "ensure that those responsible for Boris Nemtsov's killing are brought to justice."
"Though Boris Nemtsov is gone, his spirit lives on in Russians young and old who seek to build a more democratic and prosperous society," acting U.S. State Department spokesman Mark Toner said in a statement.