Hundreds of opposition activists in Russia have rallied in central Moscow to commemorate the life of Anna Politkovskaya, the investigative journalist who was murdered one year ago Sunday.

Organizers say they gathered to demand authorities solve the murder.  Rally sponsors include the opposition People's Democratic Union party led by former Russian Prime Minister Mikhail Kasyanov.

Police security was heavy, but there are no reports of any disturbances.

Politkovskaya was murdered in her apartment building on October 7, 2006.  She had written about war crimes in Chechnya and was openly critical of Russian President Vladimir Putin.

The opposition demonstration coincided with official celebrations at the Kremlin marking President Putin's 55th birthday.

A pro-Kremlin youth movement also put on an outdoor party in Moscow to celebrate Mr. Putin's birthday.  An estimated ten-thousand people attended. 

On Saturday, Russian police briefly detained five foreign rights activists who came to join events marking the anniversary of Politkovskaya's death.  The activists from Britain, Spain and Germany say they were cited by police for violations of their immigration status.

More than 60 celebrities and dignitaries signed a letter that appeared in "The Times" of London newspaper Saturday calling on Russia to bring the reporter's killers to justice, and to protect journalists.

Russian authorities have detained 10 people in connection with the murder.  Two have been released.

Some information for this report provided by AP, AFP and Reuters.