The ruse is up. Any hope that Syrian President Bashar al-Assad would abide by the UN-backed Annan peace plan perished alongside the 49 children murdered in Houla. Now, fresh reports of killings have emerged from the village of al-Qubair, near Hama: 60 citizens are confirmed dead, including 30 children and at least 13 women. The 300 observers dispatched under the Annan plan have become witnesses to murder, not monitors of a ceasefire. And Assad remains defiant, shielded by the diplomatic cover of his patrons and arms dealers in Moscow.

For followers of the daily tragedy in Syria, it is so easy to be overcome with sadness and hopelessness. But we must not let that stop us acting to end this horrifying violence.

'Sane measures' have failed

Since the Assad regime began killing pro-democracy protesters 15 months ago, a series of plans has been drawn up to end the violence. None have succeeded. An Arab League mission to the country achieved nothing but embarrassment. Two UN Security Council resolutions aimed at ending the bloodshed were torpedoed by Assad's allies in China and Russia. Moscow has sold Syria $4bn worth of arms since 2006, and keeps on selling.

The most recent peace plan, authored by former UN secretary general Kofi Annan, met with cautious approval when it was agreed in early April. It called for a ceasefire, the withdrawal of government troops, political dialogue and a collection of other, sane measures. On each of those fronts, the Assad regime has failed. The day the agreement went into effect, government troops killed six people; since then, an average of at least 37 Syrians have been killed each day. Assad's murderous disregard for the Annan plan and his own people was made plain in Houla at the end of May: more than a hundred were killed, 49 of them children.

Em Shalaan, 45, who lost her husband, three children and six grandchildren, described the massacre to Avaaz: "The shabiha came in and pulled out the men in the family and shot them in the street. I then heard one of them outside saying ‘Kill the women and children – kill them all’. I ran to the stables behind the house and hid in the hay. I could hear my children screaming ‘help me mum’. After 30 minutes I went back and found the bodies. I discovered only my 13-year-old daughter had survived, with a bullet wound in the chest.

"Why did I lose my family, what did they do to deserve this?”

Don't despair, act

The horror in Houla showcased the inhumanity of the crisis, but it was no exception. Since the uprising began, more than 14,000 Syrians have died, 1,000 of them children. With UN monitors actually on the ground and footage of the carnage splashed across the global media, the world knows exactly how bad it has got.

Today, Avaaz has delivered a 764,000 strong petition to the UN Security Council, calling for the immediate deployment to Syria of 3,000 international monitors with a mission to protect civilians. Avaaz members staged a protest outside the UN, laying out 49 tiny figures shrouded in white sheets, to represent the children killed in Houla.

“With Russia’s support, Assad has shredded the Annan plan," Avaaz's executive director Ricken Patel said today. "The world failed to stop the killing in Rwanda – have we learned from our mistakes, or will we leave the Syrian people to their grisly fate? 762,000 people are calling on the world to deploy 3,000 monitors across every city in Syria, to deter Assad’s death squads: we hope the UN will act to protect civilians today.”

Take action: Sign Avaaz's petition to protect Syria's children by sending a 3,000-member UN force to shield civilian populations, and join our call to world powers to stop the merchants of death. If you've already done both of those things, share this story with everyone you know.