More than two thirds of Russians are aware of this month's deadly Islamist attack on the Paris headquarters of French weekly Charlie Hebdo, an opinion poll suggests.

Russia's VCIOM opinion studies group told Interfax that 74 percent of respondents in the poll knew about the January 7 assault, that 23 percent had seen cartoons satirizing Muslim prophet Muhammad that were published in Charlie Hebdo, and that 51 percent had heard of the violence but hadn't seen the cartoons.

At the same time, 22 percent knew nothing about the Charlie Hebdo shooting.

The respondents chiefly blamed the assault on religious insults inflicted by the magazine on Muslims (30 percent) or on the French government's policy that allows journalists to humiliate religious people (25 percent).

On the other hand, 11 percent of respondents believed France had let in too many immigrants, another 8 percent said the brutality of several Muslim extremists had been the sole cause of the tragedy, 6 percent pointed to what they saw as poor performance by French intelligence services, while 12 percent were undecided.

The attack was condemned by 87 percent of those questioned though 39 percent said they could understand the gunmen' motives while 48 percent said there could be no justification.

The survey was carried out on January 18 with 1,600 people being interviewed.

Twelve people, including eight journalists, were killed in the assault, and 11 were injured. The gunmen, brothers Said Kouachi and Cherif Kouachi, were shot dead on January 9.

Less than an hour before the attack, Charlie Hebdo posted a cartoon ridiculing Islamic State leader Abu Bakr al-Baghdadi on Twitter.

Charlie Hebdo, which comes out on Wednesdays, features patently nonconformist cartoons, reports and jokes. More than once, it has drawn wrath from Muslims for publishing cartoons satirizing Islam and Muhammad.

Its headquarters was set on fire in 2011 after an announcement of a planned issue to be entitled Charia Hebdo (Sharia Hebdo) with Prophet Muhammad to be named as editor-in-chief. No one was hurt but the magazine's website was hacked.