INTRO: Human rights and opposition groups demand action one month after the shooting of a prominent human rights lawyer and a journalist in central Moscow.
Hundreds of protesters march through the Russian capital to voice their discontent over "political killings".
It is now almost a month since the brazen double killing in central Moscow.
Human rights lawyer Stanislav Markelov and journalist Anastasia Baburova were gunned down in broad daylight.
Human rights and opposition groups are demanding action.
Hundreds of protesters marched through the Russian capital on Sunday, carrying photographs of the victims, and banners reading "No to political murders" and "Your silence is justification of murders."
They are angered by what see as official inaction over the killing of investigative journalists and human rights campaigners.
Markelov was shot dead shortly after losing a legal battle against the early release of a former Russian tank commander - imprisoned for the murder of a Chechen girl.
Baburova was with him when he was attacked and - according to witnesses - was shot when she attempted to intervene.
She worked for the same newspaper as Anna Politkovskaya, who was shot dead outside her Moscow flat in 2006.
Lyudmila Alexeeva, prominent human rights campaigner and head of the Helsinki Group, called the rally itself, significant;
(SOUNDBITE) (Russian) LYUDMILA ALEXEEVA, HEAD OF HELSINKI GROUP, ADDRESSING THE RALLY, SAYING:
"Here only very brave people attend rallies. It is the first time in a long period when we were able to march peacefully with our slogans'."
In recent years, Russian authorities have regularly refused permission for protests in Moscow, or used force to break up unsanctioned rallies.
This one, at least, passed off peacefully.
Peter Parker, Reuters