Police in bullet-proof vests guard a military court for the terrorism trial of Varvara Karaulova, a slim 20-year-old with braided hair who clutches a page of handwritten notes.

Karaulova was studying philosophy at the renowned Moscow State University when she tried to enter Syria last year after falling in love online with an Islamic State fighter.

Karaulova's trial on terrorist-related charges is the most high-profile yet of a Russian heading to Syria -- where Moscow warplanes are bombing in support of ally President Bashar al-Assad -- and supporters say authorities are using her to send out a warning. 

A large number of the foreign fighters with the jihadist IS group in Syria are from Russia, and Moscow claims 2,700 of its nationals and citizens from other ex-Soviet republics have been killed in the anti-IS operation.

But most of those from Russia fighting in Syria come from Muslim communities principally in the volatile North Caucasus region. 

- 'I didn't join anything' -

As an ethnic Russian woman from a privileged background, Karaulova is a rarity.  

She is charged with preparing to participate in a "terrorist organisation" and if convicted faces up to five years in jail with the verdict expected in a week or two. 

She is pleading not guilty, arguing she never intended to fight but simply wanted to be with the man she loved. In court she is known as Alexandra Ivanova after changing her name to try to avoid media attention. 

"I didn't join anything, I'm not a terrorist and absolutely never intended to become one," she said at the opening of the trial on October 5, quoted by Interfax news agency.

Her defence lawyer Sergei Badamshin told AFP the justice system is making an example of her, even though "families of terrorists are not punished in our country."

"This is undoubtedly a show trial," he said. "Unfortunately, they chose a victim who has nothing to do with IS's terrorist activities."

"Why it was her -- I can't say."

- 'Winner in life' -

Karaulova grew up in a middle-class family in a leafy area of Moscow and left school with all A grades, Badamshin said. 

"She's a winner in life."  

Then Karaulova  became interested in Islam and began wearing a headscarf, and on May 27, 2015, she disappeared.

Her father reported her missing and traced her to Turkey, where she and a group of other women were caught by border guards as they attempted to cross into Syria.

After her return to Russia in a blaze of publicity, investigators initially said she had committed no crime. But almost half a year later, she was detained and charged.

She is being held in the notorious Lefortovo jail under tight supervision, her lawyer said.

At the trial held in Moscow District Military Court, Karaulova speaks clearly but briefly, and keeps a copy of the Criminal Code on the seat in her glass cage.

At one point a witness described her as weighing around 75 kilogrammes and she flares up: "Did the witness weigh me?"

She refuses to answer questions about her religious views, but is now bareheaded and wears colourful dresses, her eyes ringed in dark liner.

- First love -

She says she got to know a man through a social networking site, who used various names including Vlad, Artur Sokolov and Adam, but whose real name is reportedly Airat Samatov, a Russian citizen, who investigators say is fighting with IS.   

Her lawyer says Karaulova was going through a period of teenage low self-esteem that made her vulnerable to such tactics. 

"She's a closed, reserved person... No one knew what was going on inside her, not her parents, not her friends,"  Badamshin said. 

For her, it was first love, he says, while raising the possibility that the messages to her were not even all written by the same person, due to stylistic differences.

The prosecution is using other women who tried to reach Syria along with Karaulova as witnesses -- but they remain at liberty.

Wearing a hijab, one woman, Regina Velimetova, spoke via video link from Dagestan's Supreme Court.

She recalled travelling to the Turkish border with Karaulova. 

"She was crying, she was missing her parents," Velimetova said, adding that her companion told her she was going to Syria because she had "fallen in love" with a guy who lived there and he had "invited her to get married". 

Such women "all want to get married under sharia rule," said Velimetova, adding she also went "to seek married happiness."

She insisted: "That doesn't mean we went there to take part in military action and to blow ourselves up. Our aim was just to live where the law of Islam is observed."

Source: AFP