With global attention focused on the fight against jihadists, Syria's regime has in recent weeks stepped up its use of deadly barrel bomb strikes, killing civilians and wreaking devastation.

In less than a fortnight, warplanes have dropped at least 401 barrel bombs on rebel areas in eight provinces, according to the Syrian Observatory for Human Rights, a monitoring group.

Activist Yassin Abu Raed, from the town of Anadan in northern Aleppo province, has seen his house hit three times in barrel bomb attacks.

The latest strike destroyed it completely.

"Death is all around us, and nobody cares," he told AFP via the Internet.

"Barrel bombs kill those we love most, they destroy houses, dreams and memories, and leave us without any hope that the killing will ever stop."

"All this, and no one has even heard of us, no one feels for us."

The Observatory, which documents casualties and strikes, relying on a broad network of activists and doctors across the war-torn country, said at least 232 civilians have been killed in regime air strikes, including barrel bomb attacks, since October 20.

Observatory director Rami Abdel Rahman said the number of barrel bomb attacks is now "much higher" than a fortnight ago.

The regime began using barrel bombs in late 2012, but stepped up its attacks this year, with a wave of raids in February alone killing hundreds of people.

Barrel bombs are typically constructed from large oil drums, gas cylinders or water tanks filled with high explosives and scrap metal.

- Raids hit refugee camp -

On Wednesday, helicopters dropped four barrel bombs on a camp for displaced people in the northwestern province of Idlib, killing at least 10 people and wounding dozens, according to the Observatory.

Activists posted horrific video footage on YouTube, showing bodies torn apart and people wailing as they tried to rescue survivors.

The United States denounced the attack as "barbaric".

Ismail al-Hassan, a volunteer nurse at a field hospital in Idlib province, told AFP via the Internet that health workers face immense difficulties treating the wounded after a barrel bomb blast.

"Most of the casualties from barrel bomb strikes are women and children," said Hassan, adding that medical staff suffer from severe equipment shortages, making it hard to treat casualties properly.

Hassan also said he and his colleagues suffer deep psychological scars from treating victims.

"Once we had to decide to leave a child to die. He simply had too many wounds on his body -- we couldn't save him," he said.

Like many Syrians in rebel-held areas, Hassan resents the West's failure to help topple President Bashar al-Assad's regime.

"Everyone in Syria has realised that we only have God by our side," he said.

- Global attention 'diverted' -

In February, the UN Security Council passed a resolution demanding that all sides in Syria's war end attacks against civilians, with a specific mention of the use of barrel bombs.

The government denies using barrel bombs, and says it only targets "terrorists".

New York-based Human Rights Watch has repeatedly blasted Damascus over its "unlawful" use of barrel bombs, saying the weapon is particularly indiscriminate.

HRW researcher Lama Fakih said there had been no global effort to hold Assad's government to account.

"While there is international effort to stop abuses by (the jihadist group) Islamic State, there is no concerted international effort to stop abuses by the Syrian government, including attacks against the civilian population," she said.

The United States and its mainly Gulf allies began air strikes against jihadist positions in Syria last month, but there has been no question of extending the strikes against Assad's regime.

"Unfortunately international attention has been diverted by the Islamic State's advances in Iraq and Syria," Fakih told AFP.

Observatory director Abdel Rahman agreed.

"The number of regime air strikes including barrel bomb attacks is just crazy, and there has been an escalation in recent days," he said.

He accused Damascus of "taking advantage" of the world's focus on IS to step up its attacks on rebel areas.

Syria's opposition says international criticism of the regime is simply not enough.

"The United States criticises the regime, but it still does nothing" said Samir Nashar, a member of the key opposition National Coalition.

"Meanwhile, the regime is making military advances."