Campaigners from around the world are urging Russia to back the UN Security Council and help bring an end to the crisis in Syria, coinciding with what they are calling the one-year anniversary of violence in the country.
A coalition of 200 non-government organisations (NGOs) from 27 countries is demanding that the UN Security Council unites and passes a resolution calling on the Syrian government to stop shelling civilian neighbourhoods and stop other violations of international law, arbitrary arrests and torture, as well as granting urgent access to humanitarian workers, journalists and human rights monitors.
The group includes Human Rights Watch, Christian Aid, the Cairo Institute for Human Rights Studies, CIVICUS and the International Federation of Human Rights.
Kenneth Roth, executive director of Human Rights Watch, said: "Russia and China have twice blocked Security Council action, a defence of Assad that he has interpreted as a licence to kill.
"Moscow and Beijing should stop providing diplomatic cover for Syrian atrocities, and start demanding an end to indiscriminate shelling and attacks on peaceful protesters."
Souher Belhassen, president of the International Federation for Human Rights (FIDH), added: "The Syrian people have survived with outstanding courage one year of systematic and widespread crimes and bloodshed as the world stood by and watched.
"The international community must unite and help Syrians bring an end to the horror."
The coalition wants the UN Security Council to urgently pass a resolution calling on the Syrian government to bring an immediate end to its indiscriminate shelling and attacks on peaceful protesters, and also for the international community to provide full support to Kofi Annan, UN special representative for Syria, including engaging Russia and China in any UN initiative to end the crisis.
It also wants the Syrian government and other armed actors to guarantee full and unimpeded humanitarian access to all areas of the country in which there is a need in accordance with international law, and for the Friends of Syria group to uphold promises to provide funding for humanitarian assistance.
A Twitter Campaign has also been set up, hoped to reach several million people, with well-known Twitterati involved, including British actor Stephen Fry and singer Nelly Furtado.
Ziad Abdel Tawab, deputy director of the Cairo Institute for Human Rights, said: "For a full year, the death toll in Syria has escalated to the horrifying total of more than 8,000 dead, including hundreds of children.
"Isn't it time for the world to unite behind effective steps to stop this now?"
The coalition's call follows an announcement this week by the UN that it would shortly deploy human rights monitors to neighbouring states to collect evidence of atrocities in Syria.
Access to the country itself is almost impossible for observers.
Also this week, Amnesty International said it had fresh evidence of widespread abuses of civilians detained by security forces in the year-long crackdown on anti-government protests.
In a report that identified 31 torture methods described by witnesses, Amnesty said the situation resembled the "nightmare" of Syria in the 1970s and 1980s, when the country was ruled by the father of today's president, Bashar Assad.
Amnesty based its conclusion on testimony gathered from Syrians in Jordan - including 25 who said they had been tortured.
Its report concluded: "The testimony presented in this report, taken in the context of other human rights violations committed against civilians in Syria, is yet further evidence that torture and other ill-treatment in Syria form part of a widespread and systematic attack against the civilian population - carried out in an organised manner and as part of state policy and therefore amount to crimes against humanity."
At least 276 people had so far died in custody, it said, with security forces effectively given impunity to torture despite it being outlawed by a new constitution.