Amid the worsening bloodshed of the Syrian civil war, getting the work of the country's struggling and oppressed artists seen overseas involves serious personal and financial risk. Fadi Haddad, of refugee support group Mosaic Syria, estimates it has cost almost £30,000 to smuggle out artwork for a new London exhibition that explores the worsening humanitarian crisis.

The show, #withoutwords: Emerging Syrian Artists at the P21 gallery in Euston, includes artists who have fled persecution and those who remain in the country despite having suffered threats from or torture by Bashar al-Assad's regime. Several have lost loved ones in the conflict that has claimed the lives of an estimated 93,000 people.

"I travelled to Lebanon and Jordan twice to take work smuggled over the border," said Haddad. "The artists are worried that they could be traced if the work is stopped at a checkpoint. Some haven't signed their work. The security police wouldn't understand their message but they'd still see it as a danger. One artist went to Lebanon to remake her work just to avoid trouble from the authorities."

The exhibition, which opens on Thursday, offers a sometimes harrowing glimpse into the lives of ordinary Syrians. Perhaps the most visceral work on show is Tarek Tuma's portrait of Hamza Bakkour, the 13-year-old boy whose jaw was blown off in February 2012 during the Syrian army's siege of the rebel Baba Amr district of Homs.

Hamid Sulaiman's Light After Dark (2012) shows people huddled in a corridor of police headquarters in Damascus. Photograph: Hamid Sulaiman/Mosaic Syria

Tuma's own family has fled from and returned to their home in Douma, a suburb of Damascus, several times since the conflict began. The artist, who now lives in London and is the lead curator of the exhibition, said the painting is also a kind of self-portrait, reflecting his guilt at being an exile while his country suffers. "It's like a body without a head being an exile. My body is here but my soul is not."

Artist Hazar Bakbachi-Henriot, originally from Aleppo but now living in France, went to Antakya, Turkey, near the Syrian border last year to help women from three refugee camps tell their stories by making tapestries. The one on display shows grieving women surrounded by tombstones. "The graveyard tapestry is a reflection of what many of these women went through – they had all lost a relative or a friend," she said.

The brutal crackdown on Assad's opponents dominates the paintings of Hamid Sulaiman, from the town of Zabadani near the Lebanese border, who fled abroad in 2011 after being arrested several times for taking part in peaceful protests.

Ali Ferzat is a satirical cartoonist who in 2011 had his hands broken by militiamen after he criticised the Syrian regime. Photograph: Ali Ferzat/Mosaic Syria

On one canvas, Light After Dark (2012), abstract flesh-coloured bodies huddle shackled and blindfolded in a basement corridor of the security police headquarters in Damascus, where the artist was once imprisoned. Now living in Paris, Sulaiman said the single shaft of light that illuminates the scene symbolises the desperate hope prisoners cling to.

"Hope of the light after of all this darkness is the thing that keep you sane. I was not tortured but I saw people getting tortured and I heard their screams. I lost many friends under torture including my best friend, and I can feel their hope of the light even one moment before they died."

Hope is also present in the satirical political cartoons of Ali Ferzat, whose hands were broken by pro-Assad militiamen in August 2011. Some of the other drawings exhibited display the caustic wit that provoked his brutal assault, including one showing Assad gazing admiringly into a huge mirror that magnifies his reflection.

Malu Halasa, co-curator of the exhibition said: "For a generation of Syrian artists, the uprising has invigorated their work and revitalised an art scene that languished under dictatorship, censorship and state control for 40 years. Artists are painting blood and guts and mayhem and half the time it's their blood and guts."

#withoutwords: Emerging Syrian Artists is showing at the P21 Gallery, Euston, from 27 June to 1 September 2013