The cyber front of Syria's year-old civil war spread to Russia this week as pro- and anti-government bots splashed criticism and expressions of gratitude across the Russian Internet, and Syrian hackers attempted to commandeer the website of a Russian embassy.

The attacks are a response to Russia's ongoing resistance to proposed UN sanctions against Damascus and willingness to sell weapons to the Syrian government, which has been accused of killing thousands of civilians to stem a popular uprising that began in March.

On Sunday, the Syrian National Council, the main opposition coalition, called on Syrian expatriates to stage protests at Russian embassies and consulates and "exert pressure" on Russia.

Syrian electronic activists appear to have heeded the call, as Dozhd television said its website started receiving three to four comments per hour beginning Monday night.

Thousands of Syria-related comments have since appeared on Russian news websites and Facebook pages. Most comments are sharply critical of Russia's defense of President Bashar Assad. "Russia sold its humanity when it sold weapons to a criminal regime" user Abu Mujahid al-Hamwi wrote on President Dmitry Medvedev's Facebook page Tuesday morning.

A small percentage of the comments — which appeared in Arabic, Russian and English — expressed gratitude to Medvedev and Prime Minister Vladimir Putin, such as one from user Hamoud Youssef: "A heartfelt thank you to Russia. … Thank you for the veto."

The comments were ostensibly posted by users with Syrian-sounding names, but the high number of identical entries suggests that the effort is largely automated. Several comments appeared dozens of times from multiple users on Facebook pages belonging to Slon.ru, Afisha, and Lenta.ru.

Meanwhile, a senior official at the Russian Embassy in New Delhi said Syrian hackers tried and failed to commandeer the embassy's website, Vesti.ru reported Monday. The official denied earlier reports that hackers had posted photographs of children allegedly killed by Syrian security forces.

For months, Russia and its allies have resisted growing pressure from Western governments and much of the Arab world to take a harder line against the Syrian government, which opponents say is using tanks and heavy weapons to slaughter opponents. The UN estimates that more than 5,000 have died in the crackdown.

The Syrian government says it is battling terrorist groups, and Russia has called on both sides to reject violence and come to the negotiating table. In October, Russia and China blocked a UN Security Council resolution calling for sanctions against Syria within 30 days if the government did not stop attacks on protesters.

In December, Russia agreed to sell 36 Yak-130 trainer-fighter airplanes to the Syrian government in a $550 million contract, Kommersant reported this week. Last month, a Russian-owned ship laden with munitions arrived in Syria after being temporarily detained in Cyprus.

Analysts have speculated that Russia is eager to hold on to a longtime ally and prevent a repeat of NATO's intervention in Libya. Also at play are billions of dollars worth of arms contracts and a naval base in the Mediterranean city of Tartus, Russia's only military base outside the former Soviet Union.