Armed with camera phones activists are posting hundreds of videos on the internet every day documenting the civil war

In April last year Ahmad Mohammad left his village in northern Syria filled with its pomegranate trees, figs, and goats, and moved to Lebanon. He came back five months later with a certificate in mobile phone maintenance – a weapon more powerful than Bashar al-Assad's helicopters and tanks.

While he was away Mohammad learned how to upload videos to YouTube – a website banned by the Syrian regime. "Nobody in Syria knew how to do this," he said. In the meantime Syria's revolution snowballed from a handful of protests into a seething nation-wide revolt, characterised by nightly anti-regime gatherings, shootouts with the security forces and a growing number of casualties.

Mohammad had a laptop but no money. His brother lent him some cash, with which he bought a 3G modem and a Sony Ericsson phone from Turkey. Within a couple of days, he had rigged up a high-speed internet connection at his parent's home – the cable sitting next to the vine above the terrace and a pot of basil on a wall.

Last autumn opposition fighters took control of his village. On 10 January 2012, Mohammad shot his first video, a demonstration, on which did a voiceover in Arabic: "Don't trust Assad's reforms, join the revolution!"

The day was muggy and wintry; the picture quality wasn't great, with sepia tones. But Mohammad's career as a video activist had begun.

Across Syria hundreds of video activists – most of them young, male, and technologically savvy – have joined the revolution against the Syrian government. "The regime is fighting the people in two ways. One is with the army. The other is with the media," Yahya Abdulrahman, a physics student from Aleppo University explained.

The 21-year-old, who is from Aldana, north of Aleppo, added: "There are parts of the Free Syrian Army that are fighting the regime. But there are other parts fighting the regime's hackers." Aldana is without an internet connection, so Abdulrahman, also a video activist, typically gives his Nokia memory card to Mohammad to upload.

Abdulrahman took his first video of a demo on Aleppo University's science campus. He said he got the job because he was tall and good at running. During his second assignment, however, the security forces caught and arrested all of the students involved. "I was shooting video. Five guys grabbed me," he recalled.

The police took them to Aleppo's Baath party headquarters and beat them up. "They piled us one on top of another. Then they stood on us," he said. He was eventually released – after more beatings from the army – and signed a document saying he wouldn't attend any more protests and would work as an informer. Days later he was filming again.

Even before Syria's bloody uprising began in March 2011, Abdulrahman said he and his fellow students had been involved in a cat-and-mouse game with the authorities, using proxies such as simorf and ultrasurf to access their Facebook accounts. (The regime banned Facebook and YouTube, but allowed internet mail and Skype.)

Another student, Abu Omar, recounted how he spent 11 months in jail – including five months and eight days in solitary confinement – after joining a Syrian exiles' Facebook page. "They traced my IP address," he said. "The army asked me: "Do you use internet?" In jail, they made me spend a week standing up."

The Free Syrian Army now controls much of the countryside and has created its own rustic mini-empire in the north and east. But Syria's cities remain largely with the government. The armed opposition failed two weeks ago to seize parts of Damascus, but on Monday overran an army checkpoint just north of Aleppo, bolstering its forces inside the city.

On the internet, however, it's different story. The regime is being trounced. The opposition posts hundreds of new videos every day. There are sites, such as Omawi news, dedicated to the latest from the revolution, new opposition satellite channels, users such as Anadaaan posting dozens of videos, and live streams from embattled anti-regime towns such as Homs and Hama.

Some of the footage is extraordinary: vivid, raw, gripping scenes of urban warfare. One eight-minute video from Aleppo posted last week shows rebels from the Tawhid United brigade, one of the largest fighter groups in the city, ambushing a tank column in the Hanano district: the tank's barrel swivels towards the fighters; one man fires rocket-propelled grenades at it followed by another; there is the cacophony of gunfire, smoke, chaos, cries of "God is great" and "The driver escaped!" Smoke billows across wobbly alleyways; you can almost smell the adrenaline and fear.

Following early successes each FSA unit now operates with one or two video activists. The activists are armed with Kalashnikovs and camera phones – the instruments of 21st-century warfare. "When the enemy is shooting you it's very hard to get out your camera," said Abdulrahman. "Sometimes I put it away and reach for my gun. If the army sees anyone with a camera they try and kill him first."

The activists also capture the ebb and flow of ordinary life – and death – in opposition-controlled provincial towns. To begin with Mohammad filmed his neighbours from behind, anxious for their faces not to be seen.

"In Aleppo there are a lot of Bashar supporters, searching uploaded videos. If they find someone they know they put them on the wanted list," he explained. "I'm on the list."

He uploaded a protest in nearby Aldana filmed by Abdulrahman, from a balcony above a small shop in the dusty town square.

The crowds shout "Death to Assad" and wave a revolutionary flag, the green-white-and-black pre-Ba'athist tricolour. At the beginning Abdulrahman holds up a piece of paper with the name and time of the protest, to counter, he said, regime claims that such demonstrations were faked abroad. Last week the regime shelled the same square; five people were killed, three of them children.

Other videos feature a tank column on the move; a decidedly tuneless revolutionary protest; and a fighter allegedly killed in custody by Assad's military intelligence.

The sign on the body reads simply "Ahmed Mohamad Issa; died 2/27/2012".

Martyrology has become an important component of the rebel struggle – a way, activists say, of chronicling the regime's crimes and transmitting the truth to the world. Another gruesome video shows a young man, Abed Arauf Jamil Al-Moeddin, stabbed to death in a small north Syrian village by his pro-regime neighbours.

The activists even video dead children, a task they say is heartbreaking. "I filmed one of the children killed last week. We hadn't eaten all day because of Ramadan. But afterwards I couldn't touch any food," Abdulrahman said.

Mohammad's video skills, meanwhile, have dramatically improved. Over the weekend he went on a hair-raising trip across the frontline into Aleppo, filming out of the window along a forested sniper's alley. Inside a rebel-held area, he took further footage of Free Syrian Army checkpoints. He filmed a slick and atmospheric portrait of a metropolis of 2.5 million people, terrified, hungry and under attack.

The Syrian government has fought back, of course. The regime has for months refused visas to all but a handful of foreign journalists to visit Damascus. And it has restricted those allowed in. Channel 4's Alex Thomson – one of few correspondents granted a visa – last week tweeted his frustration at not being allowed to film the Syrian army. "Syrian government is losing the PR war," he wrote.

For its part, Syrian state TV remorselessly brands the Free Syrian army "terrorists" and "al-Qaida". Its main Addounia channel broadcasts a mixture of soap operas and pro-regime propaganda. Syria's official news agency, SANA, meanwhile, maintains the situation inside the country is normal, that calm has been restored, and the weather is pleasant. Syrian regime trolls tweet hate-mail to journalists who have slipped into the country, as the government's control crumbles. "I pray every night that you die," one message sent on Saturday to this Guardian journalist.

Despite these half-hearted efforts, the regime has comprehensively lost the electronic war against its YouTube generation enemies. And by slow degrees, it is losing the other battle too.