"They released us after four and a half hours, the five foreigners," Neil Hicks, of the New York-based group Human Rights First said on Saturday.
  
"We think is it interference in the activities of human rights organisations," he said. "It is unfortunate and shows the problems with basic freedoms are very severe in Russia."

Memorial events

Hicks, who was fined $120 for a violation of his visa status, will travel to Moscow on Sunday with the other activists to attend the anniversary memorial events.

"We call on
the Russian government
to bring to justice ... both those who killed Anna Politkovskaya and those who ordered her murder"


Letter from 'Reach All Women in War'
Politkovskaya was shot dead outside her home in the Russian capital on October 7 last year.

Russian authorities have arrested 11 people over her death and last month prosecutors charged a former Chechen official as an accomplice to the murder.

The government-run Rossisskaya Gazeta newspaper, citing unnamed law enforcement sources, reported on Saturday that a Ukrainian crime boss had also been arrested in connection with the killing.
   
Prosecutors, who link the murder to her reporting, have said they suspect she was murdered by an organised crime group involving serving and former law enforcement officers.

Last week, Reporters Without Borders, a Paris-based media freedom watchdog, criticised the inquiry into her murder and expressed doubts "about the will of the authorities to really solve this murder".
   
Politkovskaya was active in exposing abuses by security forces in Chechnya and neighbouring Russian regions. She was also an ardent critic of Vladimir Putin, the Russian president.

'Attack on democracy'

Earlier on Saturday, the Council of Europe repeated its call to Moscow to reveal the truth about Politkovskaya's murder.

"The murder of Anna Politkovskaya, one of Russia's most courageous journalists, was a direct attack on democracy, and it must not go unpunished," Rene van der Linden, who heads the pan-European rights body's parliament, said.
  
"I renew my appeal to the Russian authorities to do everything in their power to bring the truth to light, and to the Russian parliament to follow the investigations closely."

Meanwhile, a group of activists calling themselves Reach All Women in War made a similar in a letter publishe in The Times newspaper.

"We call on the Russian government to bring to justice, in full conformity with international standards, both those who killed Anna Politkovskaya and those who ordered her murder," the letter said.

Among those who signed Saturday's letter were Elena Bonner, widow of the late Soviet dissident and Nobel laureate Andrei Sakharov, former Czech president Vaclav Havel, and Marina Litvinenko, whose husband Alexander died in London last year after being poisoned with radioactive polonium-210.